I've got a Sony Bravia 32" and sorry, but for me the SD picture is poor compared to the SA V+ box that's been moved upstairs.
As people have said, channels like BBC1 which looked HD like when in SD, look like the Freeview equivalent now

The lower bandwidth channels are on the verge of awful.
HD, to be fair, looks at least as good, if not better though.
Had a play with all the settings and I can see little difference in SD picture quality. I supposed it's a question of playing around and seeing what works best. At the moment though, slightly disapointed.