The only thing that is not comparable is that the 360 can upscale both horizontally and vertically.
Did not know about that. Interesting. Although I still wouldn't mention it as comparable to what the 360 does in any way. And does it still tax the same hardware used for the games, or is it truly dedicated like the 360's upscaler? If it was truly dedicated I can't imagine why more games wouldn't do this (seeing as how 960x1080 is not many more pixels than 720p). Unless it doesn't really look much better (which is probably the case since it's not many more native pixels, but it would still be nice to not rely on my TV's upscaler).
I don't know which chip exactly does the scaling on the PS3 but I don't think it's the RSX.
edit: I think it was supposed to be done by the SCC because it definitely contains 2 scalers, but I don't know if it was ever proven or not.
On the 360, there were talks of that magical (H)Ana chip ages ago but that was debunked shortly after. As far as I know upscaling is done through the Xenos.