Hey, Bassboy,
The Cakewalk/Sonar stuff is compatible with the Tascam item, as well as any of the Cubase packages. Quite a bit will work with it. I'm using Cool Edit Pro 2.0 with mine, and the only thing CEP won't support is the Assign and one other button (I can't remember!) for which there is an alternative, 'nothing' procedure instead. And CEP will take as much simultaneously as you can get into it (got 128 tracks. Why not...) It's now called Adobe Audition...
I will say that I'm having an issue with volume: This just came on: I was fooling around with an old Yamaha drum machine (RX120) going into the US-428, and suddenly experienced a pretty quick decline in volume, down to nearly no volume at all! I got the problem fixed, but it's noticeably a bit lower overall than it was. I have to get a new motherboard, so maybe that's it. I also just got (same day) an additional 128 MB of DDR RAM. And just before this happened, I turned on the 428 with my Fostex monitors already on (oops!), and they have their own little amplifiers in 'em... So it's unclear what happened.
Otherwise, it's been fine! BUT you might look into the Event EZ-Bus, and the SI-24 bundled with a scaled-down Logic program from Roland. Good reviews on another forum with that one. Might be a few more bucks, though. Also Edirol gets good marks from Sound-On-Sound magazine for their USB controller/interface. AND, Behringer sells a couple controllers, for cheep, but you'd need a separate sound card I think.
I did some shopping before and after I got my 428, but no regrets. And the 428 can be had new for $100+ less than when I paid for mine! (I hope the issue I mentioned above won't be a 428 issue, though; but it's the first such complaint I've heard.)
Have fun in your quest!
Rog.