In a world full of half-working, poorly-designed products, UD is a standout. It's pretty rare that a small company not only produces a great product, but actually supports it, enhances it, and builds it well. (Ok, I'm sure they contract the building out, but whoever they're using does a good job.)
I'd recommend an ISY to anyone that wants control over their SmartHome Insteon devices. I tried several SmartHome controllers in the past, and as is typical with them, they sort-of worked for a while, and then didn't, and were never supported or updated. Not the ISY. It just works. If you have some setup that doesn't, they really work with you to fix it, and then that fix gets rolled into the (frequent) firmware updates.
My only concern is that the ISY uses a SmartHome PowerLinc modem, but so far that's worked reliably. Actually, I have to say, the SmartHome Insteon devices seem to be far more reliable than previous SmartHome products, so maybe they're getting their act together, too.