I've got the Ketron SD2 and a new Roland SD50 sitting right next to each other. I like them both, they cost me about the same, and sometimes I can't decide which I like better for a particular song. I bought the Roland mainly because its combination of features (midi, usb audio interface, etc.) is a real plus when I just want to work with a laptop, and -- based on on reviews -- I expected to be blown away by its sound. Well, I wasn't. Maybe I'm jaded now that I spend so much time with RealTracks, but to me the SD50 sounds good, but not light years ahead of previous generations of Roland midi gear -- and certainly not better than the Ketron. The Ketron is great for general midi, but really shines in some sounds in its upper banks that are just gorgeous. I do think my Ketron might be just a bit noisier electronically than the Roland SD50 -- I'm talking about something you'd probably never hear in a mix. With any encouragement, I could probably post a few BIAB-created files using both synths for a side by side comparison... unless somebody has already done this.