PCIe Syba TI chipset Firewire controller for $25 is the card I used for the brief period I used Firewire with my FF UCX.
 
See Newegg.com for good pricing.

Thanks for the replies. 
Have any of you tried to use it as a live mixer ? 

I definitely use it as a live mixer. I have mixed 5 live gigs using it to date, so not tons of experience (could be more than 5 but at least 5).
 
I REALLY like it. I like the compressors and EQs so much I've started recording the sends to the mains using loopback on the ADAT channels. What I do in Sonar ends up being great practice for mixing bands live. I can even save all the EQ Settings for a particular band and pop them back up.
 
The reverbs are wonderful.
The echo is an addition to the Reverbs really. It can be used independently (only echo no reverb). What you can't do is send 5 tracks to reverb and 1 track to reverb AND echo. The FX bus has Reverb and Echo inserts. Everything sent to that bus gets the same pairing of those two.
 
Now Reverb and Compression/Expansion IS track by track.
 
I have done real time bounces within Sonar to apply the reverb from the UCX to a mix. I have not really used the compressors for real time bounces, but I do use them when mixing live. Keep in mind that for this purpose you can use the ADAT channels too. So you can Send 18 44.1 tracks through the EQs and Compressors in the UCX and bring them all back into Sonar for mixing. Not sure it's worth the effort, but think about it.
 

RME Help File
FX Send. Setting the level of the signal sent to the FX bus which feeds Echo and Reverb. The current setting is also visible with closed channel settings, because knob and small fader are always synchronized. To make this function as useful as possible FX Send is locked to the highest submix, thus imitating the Aux Post Fader function of a standard mixing desk. When moving the big fader both knob and small fader will move. This way the reverb signal will always have the same relation to the dry signal.

I want to add that RME also comes with DigiCheck. This means that you not only get the EQ and compressor/expander on every channel with sends to Reverb and Delay bus... You also get the fantastic Level Meters, Spectral Analyzer, Vector Audio Scope etc. These can be saved in Workspaces so it's possible to open 10 instances each metering a different input over time. This gives you a way to get K-System measurements real time during the concert and to limit the metering to the performance of the Sax, say or some other instrument that isn't constantly playing.
 
It's a great tool for helping set levels and EQ out to the mains.
 
Additionally, I had my computer lose power during a set break and everything kept running (mains) while I rebooted.
 
Really, I couldn't be happier with it. I've learned SO much!

The UCX allows you to save mix Snapshots during the show.
 
So, in the sound check, you enable phantom power on some tracks... maybe Inst on line ins direct from amplifiers. Now, click Store and save it as submix 1.
 
Next, your start adding EQ and compression to your various tracks. Click Store and Submix 2.
 
Now, get a little daring with the EQ. oops. Click the submix 2 button to undo.
 
The band asks to hear themselves without FX to trouble shoot a problem. Hit submix 1.
 
Problem solved, turn FX back on. Hit submix 2.
 
Try out different reverbs (save to submix 3,4 and 5). These will be used for different songs so the reverb stays fresh and interesting. Between songs, change submix.
 
See? Really lots of possibilities.
 
At the end of the Show, save the workspace for the Venue and Band.
 
Next time you're at the club, pull it up and you have all your EQ work, track naming, compression/expander settings, Reverb Sends up in a second.
 
Workspaces for DigiCheck are saved separately, but equally useful. Workspace includes graphical positioning of the UI for multiple instances of the programs. So, when you set them all up side-by-side and save as a WS, they open back up just the same.
 

Thanks gswitz (and everyone else) for all info .
I think I'll pull the the trigger and buy this unit.
Seems like it's a peace of gear the can last for a long time with all it's possibilities.

I'm running an RME UFX via USB and it's very solid - very happy with it.  No issues.

Via USB no problems whatsoever...love the unit. Haven't tried FW.
 
Regards,

I am an ultra-power user and have no issues using this about 20 hours a day.

Just ordered it. Cant't wait