I've just received my UFX today... and I'm loving it.

It's heaps quicker to get around the unit menus than I'd dared hope, which is great news; I had wondered if the mic gain adjustment was going to be kinda frustrating... but so far it seems sweet.

My feature request is to do with the record button operation:
While the unit is already recording to USB, it'd be awesome if you could press record and have the device write off the existing file and begin the next one at the subsequent sample.
I'm used to using the Sound Devices 722 and 744, which include this feature. It allows a session to be split into takes and makes logging so much easier than messing around with time refs.
If there was a concern of 'double tapping', something like a 1second lock off would suit me fine (though it's never an issue with the 722/744 in my experience).

Pre-roll (again, like the Sound Devices) would be amazing too - but I'm guessing that'd have to be designed into the hardware from the outset...

Cheers,
Michael