I just thought of a question that Jim may know the answer for... while I'm sure I'll have great performance using this via USB 3, I was kind of wondering if my current board would support an add-on PCIe Thunderbolt card and if it would make much of a difference if so. 
 
Current PC is:
StudioCat DAW with Asrock X97 Pro Chipset and I think it's a 4700k i7 CPU.  Of course I didn't type this out while I was in front of that computer early this morning, I'm doing it from another.

I looked in the BIOS and there was an option to enable Thunderbolt, but I know it's not actually built onto the board.  Just wanted to check and see if it is possible.

Thank you

Just get your interface and enjoy it with usb before spending more. I'm sure it will be terrific.

Yeah, it will be fine with USB3 on this one.  I had a couple of emails with Jim and he confirmed that I need a new board, etc to be compatible, and also said that USB3 is great with the UFX+ until I decide to get a new DAW.  I'm at least a couple of years til my next DAW upgrade, and want to make this one last even longer than that.  I'm hoping this interface will last me as long as the FF400 has, and I'm sure there is enough use left out of the FF400 that the next owner will find it nice as well.

My UFX is quite capable of very low round-trip latency over firewire (using a TB to firewire adaptor) and USB3.

I really doubt any reduction TB may manage to deliver would be noticeable in real world terms.

The UFX+ arrived Monday afternoon. I have some important family things going on, so I had limited time and so far have only had a chance to play a few tracks that I recorded with the other interface. I played around with it for awhile and figured out some basics and went to bed.  Naturally midnight insomnia kicked in and instead of waking up and snacking, I got up and did some more listening and a little mixing.
 
Small issue out of the box.  It would play through a song in Studio One, and when it would finish and rewind to the beginning it had this horrible, harsh noise that would play until you close Studio One, and it would close with a crash.  Never happened on the old FireFace 400.  I double-checked that I had the latest driver, and noticed that they had a firmware update utility that I hadn't downloaded previously.  I ran that, and found that it was pretty outdated right out of the box, and the firmware update cleared things up completely.  I'm guessing the driver was a few versions newer than the firmware and it may have caused a conflict.
 
In playing back a few songs, I thought it sounded a bit different, like maybe the stereo imaging was better, highs a bit smoother and mids more detailed.  I have also been using a Presonus headphone amp what my mains were also running through, and since this has two headphone outputs, I figured I'd try connecting everything directly and bypass the headphone amp.  Even better than I first thought.  This thing sounds amazing.  I don't think I ever quite realized how much that little box changed the sound, but it took things to a whole different level removing it from the chain.
 
On the topic of low-latency and buffer settings: this thing has no problem with handling a setting of 32 samples.  I did happen to notice that the reported round-trip latency in Studio One was insanely low at 64 samples:

• 6.08 ms for audio and 4.24 for instruments.

At 32 samples, I think the audio was slightly lower and the instruments was slightly higher, but it really wasn't enough to even be concerned about, so 64 it is for me.
 
I may not have time to really dig into doing any recording until the weekend, but yeah, I like this interface.  They actually improved on the old tech I've been happy with for years, and I have a feeling this thing is going to last me quite a long time.

Yay