It's really difficult to say because maybe my perception has changed. When I first got my installation date I basically deleted all the SD content off my V+ box and from then on have pretty much exclusively watched HD ever since.
Maybe I have just got so used to HD that SD just looks worse now ? If anything I would say it's a little softer. Particularly low bit-rate stuff. But really SD is a non-issue for me, I so rarely watch SD stuff now. 1 TB hard drive 3x thumbs up