Any reason I SHOULDN'T move to a USB interface??

I agree with Alex.
 
Besides that, if you have a firewire port, what else are you going to put on it?
 
Whereas, the USB ports usually get shared a lot. 
 

I certainly see your point and you make a great case. I just hope I can get by for another 6 to 12 months.
However, if I can't, at least you have managed to sway me back to the realm of firewire.

Which brings up my next question...I read that the firewire Focusrite units have a Texas Instruments firewire card and therefore work best with other Texas Instruments firewire cards. So...that is what I have installed on my DAW PC. Any truth to this??

I always thought a firewire card was a firewire card...but I have been reading where a lot of people say they had to replace their cards due to incompatibility. Who knew?

Does anyone have any knowledge of such a thing??

slartabartfast
According to the manual your motherboard has a VIA VT6308 controller supporting 2 x IEEE 1394a (firewire) ports http://dlcdnet.asus.com/pub/ASUS/mb/LGA1366/P6T_Deluxe_V2/E4398_P6T_Deluxe.pdf

Yes...that's true as of right now. I forgot to mention that I will be installing a new ASUS motherboard to go with the new Haswell chip. The new MB has no firewire inputs at all, so I will be installing a Texas Instruments PCIE firewire card.

WOW...Thank you so much for that link Alex. Here is a direct quote right from that article...
"We would recommend using either a Texas Instruments or a VIA FireWire chipset to avoid any such issues."

Looks like I'll be good to go either way. Thank you very much for your time and input everyone. I truly appreciate it.
HAPPY HOLIDAYS!!! I hope Santa brings you lots of fun toys for your studio.

There is no reason you shouldn't use a USB audio device. It will perform as well as any other within its design limits. I have a USB audio mixer with 16 in 2 out and I have had no problems using it. It is USB 2 and that is the most common USB support.  

I was in the same exact position just a couple of weeks ago having to choose between the  Saffire Pro 40 or Scarlette 18i20. I chose the Saffire and stayed with Firewire simply because I had exceptional performance with it. I wasn't sure if I'd get the same level of performance from USB. One thing I can say is the Saffire Pro 40 is an amazing piece of hardware for its price point. I absolutely love the thing and it is Thunderbolt ready so if I ever need to upgrade in the future I will be able to do so.  Good luck with your decision.

I have been working with a MOTU series 828 from the Mk II to the Mk III to the Mk III Hybrid and have found the Firewire 6 pin standard (Firewire 400) to be superior to USB 2.0 - because of the DUPLEX nature of packet handling, and possilby the fact that MOTU has to convert the USB protocol.  Before I post the transfer speeds of the relative technologies, it is important to note that it is not the speed, but the packet processing communications protocol employed which is important.  Namely whether or not the standard uses DUPLEX communications as opposed to HALF-DUPLEX communications.  In half-duplex, only one transmitter may speak at a time, so it is like a single tunnel through which trains must pass while traveling in opposite directions.  One train must wait for the oncoming train to clear the tunnel before it can enter and continue - so that fact that the train travels 30 mph or 35 mph through the tunnel is of little consequence - if it still spent most of its delay time in the waiting queue.  So Duplex protocols mean that travel can happen in both directions at the same time, which is THE biggest deal, much more important than transmission speed.
 
The key is not transmission speed, rather the following in my best, experience.  This is why - my MOTU picked up in performance when I switched from USB 2.0 to a PCI-e Firewire 400 card.  The extra 80 Mbps in the USB 2.0 was rendered moot by its half-duplex protocol.  Ideally then, USB 3.0 is the best of all worlds, provided the chipset compatibility issue is negated.
 
Level of Importance
1.  DUPLEX communications over HALF-DUPLEX

1. USB 3.0  -  DUPLEX
2. Firewire 800 – DUPLEX
3. USB 2.0 – HALF-DUPLEX
4. FireWire 400 – DUPLEX
5. USB 1.1 – HALF-DUPLEX

2.  Chipset compatibility
      TI or VIA Chipset 2012 and beyond - replace older resident sets with PCI-e expansion card
 
3.  Transmission Speed

1. USB 3.0  - 5000 Mbps (or 4 GB/sec)
2. Firewire 800 – 800 Mbps (or 75MB/sec)
3. USB 2.0 – 480Mbps (or 60MB/sec)
4. FireWire 400 – 400Mbps (or 50MB/sec)
5. USB 1.1 – 12Mbps (or 1.5MB/sec)

I posted the question on the RME forum, curious how they would answer.
 
http://www.rme-audio.de/forum/viewtopic.php?pid=91631#p91631
 
 

IMO the wild variances and lack of standards in Firewire chips and interfaces is enough reason to stay away from FW interfaces if you are buying something new. Works on your computer now...might not work on the next one, etc. Its future is murky as well.
 
USB 2.0 is standardized, reliable, and plenty fast enough for most recording needs. Very high simultaneous track counts at low latencies is where USB 3.0 and other formats like Thunderbolt show promise. I've been using USB interfaces for years now after using PCIe and FW and don't see any down side personally. You must however makes sure you get a product with a solid, low-latency USB driver as it will make or break your experience.

I have the RME UFX and the Tascam FW1884.
Now admittedly the 1884 is "orphanware", but the UFX is not.
In doing a little research at the RME site, they feel the USB port is "faster" on most systems than the FW port (UFX has both); seems there are more "hidden" buffers with the FW.
The 1884 is very "picky" about the chipset, but again has been orphaned so maybe not the "best" yardstick.
You do (or should, we are back to the UFX here) make sure the USB port its on is not "shared" (device manager).
Jim Roseberry walked me through all that...
Just my nickle98,
Tom

Firewire is faster on sustained throughput, but irrelevantly so for many applications. And certainly when only tracking a few tracks at the same time. I would definitely go with USB for future compatibility.

Yet every computer has a USB port and will for a long time to come. Firewire has been on its way out for a while.

I like the feedback on the Scarlett/Focusrite I/O's - this is good to know.  And yes, eventually if Firewire does not produce a standard which competes with USB 3.0 - then I am totally onboard USB 3.0 - especially given the reality that every device out there will need to employ it as at least an alternative, in order to sustain any kind of sales.  But that being said here is my experience on the upgrade pathway over the last few months inside a Gen 4 i7 box about 3 months old.  I would stay away from USB 2.0 sound.
 
I.  Firewire 400 PCI-e (Non TI chipset) to Firewire 400 MOTU 838 mkIII - Stable and clear but drivers would degrade after 1 - 2 hours and with any power saver or screen saver activity.  Livable.....but ehhh.....
 
II.  USB 2.0 Native (Intel(R) 8 Series/C220 Series USB Enhanced Host Controller - 8C26) to USB 2.0 MOTU 828 mk III Hybrid - Stable for 10 to 40 minutes and began to have ASIO integrity loss without a triggering event.  ASIO drivers had to be continually reset.  Could not employ over 8 tracks or 6 active VST 2 live effects while drivers were functioning without significant crackling and popping.  Windows 8.1 upgrade introduced a system event which would corrupt drivers totally.  Could not find or eliminate this after working for weeks with Sonar and MOTU.
 
III.  Firewire 800 PCI-e (TI Chipset) to MOTU 828 mk III - Completely stable and unaffected by system events, no ASIO driver loss observed thus far, with the system on for 8 hours continuous (never attained that before). Fastest total system speed I have had thus far :
 
2.4 msec - 226 samples
2.9 msec - 276 samples
5.2 msec - 502 samples  (96 samples per millisecond duplex compared to 44 duplex for Firewire 400 and 53 half-duplex theoretical for USB 2.0 -which I never actually could use)
 
But remember it is not JUST the line transmission speed but the inability to prioritize instruction packets versus sound, when operating in a half-duplex communications protocol with USB 2.0 and the degrading of drivers with a non-TI chipset.  The Windows 8.1 thing seems to have disappeared with the new Firewire 800 PCI-e TI Chipset card.  This despite my computer only being 3 months old; the native USB drivers/chipset seemed to have problems.  I have no idea why (maybe the chipset, maybe USB 2.0 drivers used), but I am glad it is gone.  ...whew.  

Always good to hear from multiple sides. Though your results perhaps say more about MOTU than about USB. So far I've used succesfully on USB:
1. Avid/M-Audio Fast Track Pro
2. RME UCX
3. Edirol UA25EX
4. Reloop DJ controller/interface
5. Behringer X-32
6. Pioneer DDJ-T1
7. NI S4 mk2
8. Korg Kronos using Asio4All
 
No issues with any of them other than the odd driver update. It's worth noting that not all USB ports are identical. Some will be attached to a hub inside and some supply more/better power than others. This is especially true for laptops and very impprtant when using bus-powered devices.