Just to update, when I originally raved about the S370 I had only tested it by going through my Blu Ray collection, where it beat the PS3 hands down for picture and sound.
Today I've been through several DVDs and, to be honest, I was a little underwhelmed. I think the PS3 does a better job of upscaling DVDs than the 370, though it's not better in every respect. The picture via the 370 is more stable, while motion is also handled better, though this difference is marginal.
What's lacking with the 370 though is a vibrant picture with DVD playback. There's just a discernible lack of pop and contrast, and no amount of tweaking of settings on either the 370 or my TV produced a picture I was happy with. When I played the same discs using the PS3 the problem was immediately resolved.
So, in my opinion (and I've compared the two as exhaustively as I could throughout a Saturday afternoon), if you're only interested in Blu Ray playback the 370 is a surefire winner. If you also want it to substitute as a DVD player then it does a competent but certainly not a flawless job, and is outmatched by the PS3.