Yes, I use it on conjunction with Cubase5 and it works great. plugged it in and it worked right off the hop. No problems to report, has made life a lot easier with having to deal with the mouse 24/7.
I brought home the US-224 a few days ago. I'm still playing around with it, and I haven't bothered using it with Cubasis (I've got N-Track, why go anywhere else?), but, as with someone's else's experiences with the US-428, I installed the drivers, plugged it in, and off I went.
Mic preamps are pretty good, and with the ASIO drivers, my pops and glitches were down to a bare minimum. The big diff between the US-428 and the 224 are the amount of functions (duh!). I'm having to do without the AUXs, EQs and some other knobs, plus, of course, two less XLR and MIDI i/os. But what I lose in functions I make up for in poratability. NO MORE WALLWARTS FOR ME!!
I'm also using this box in conjunction with my VXPocket2. Just know that this thing does NOT like to share, and if you use this box as an output with another card being your input, your playback will be limited to 16-bit.