I wouldn't say I was blown away, but Sony's PS4 conference certainly surprised and impressed me much more than I expected.
There's some cool stuff coming, but also some bad - the lack of built-in back compatiblity is an obvious disappointment, and there wasn't any talk about how the PS+ stuff I've accumulated will move across, if it does. Not the end of the world, but I don't have space for both a PS3 and PS4 under my TV so if it comes down to a new machine versus the current-gen box with all those games, I know which one I'll choose.
I wasn't expecting to be blown away by the graphics in any of the games, and certainly not by Killzone of all things. But that demo - as scripted smoke-and-mirrors as I know, in my heart, it was - was stunning. There's enough minor things - LoD pop-in, jaggy shadows and textures - to convince me it was running in-engine and the camera movement strongly suggests it was captured from gameplay.
The hands-down winner though, for me, was Media Molecule's sculpting/puppetry game. The creation aspect, as with Little Big Planet, doesn't appeal to me much (I'm not very good at that stuff), but the puppet show musical at the end was so unexpected and fun that I couldn't stop myself laughing.
It's going to be tough for Microsoft to follow up, but not necessarily because Sony's machine has any innate advantages - the big issue they're going to facing is that any of the multiformat stuff they've got to show as well isn't going to be new.