Running the game at a certain resolution doesn't mean that the graphics were designed for that resolution. You could hook up to a 30" apple monitor and run at some obscenely high resolution and your game textures will still be the same old assets used at 1024x768. The only thing that will change the game quality is the high/med/low texture qualities and other similar video options. This collection features revamped character models and environments, which means it will look much better than the original release.
That is why I was asking about the textures. But that isn't totally right. Running a higher resolution and using AA and AF can improve the graphics of a game as well. But not to the level of redone textures and models, or even the cut scenes. Look at the cut scenes of the redone god of war series. They look horrible...
The reviews I have read did not say what was done to update the game to HD other than it ran on a PS3. And that was the reason I was asking.
If you've picked the games up at steam and are running them at 1080, you're basically getting the same experience and there is little to no reason to pick these up. The only real addition is trophy support, which you are trading for a downgrade in the sound design (seriously, the mix is badly done, with sound effects and music cutting out or mixed improperly through your channels). If you don't already have them, it's worth a look, but otherwise, stick with you original purchase. Hope this helps.