I had planned to take full advantage of the 30-day trial, but after just a few days I was hooked. S3 is retired.
The HD interface (even with a few gaps here and there) is very nice, the guide, PIP and other assorted features are all good updates. Lag is there, but nothing was not already accustomed to in my old S3. It is by no means a show stopper for me.
4 tuners is the clincher - MOT cable box was already going back with the addition of this XL4 (used the MOT box as a "live" 3rd tuner); today's OnDemand addition is just gravy.
I've had none of the rebooting, channel issues as posted by others here...