If I remember right the wonky speed on the PS2 collection is a pretty big issue with getting some combos to work. I believe there's a couple combos that don't work on the Dreamcast (notably some Machine Gun Upper ones with Dee Jay) but for the most part it's the only way to go on console. It's why they reused it for HD Remix's classic mode!
Regarding the Capcom collection that has the first three SF2 games on PS1 (I think they just reused it for the PS2 volume 1 collection) I've never noticed anything weird about it. But then, I've never really sat down and tried to see what inaccuracies are out there.