I don't have a PS3, but I have a PS2 and Xbox. I don't like using the games systems as a movie player for several reasons:
1) It wears out the system faster.
2) I find that picture quality on a standalone DVD player is much better than on the PS2 and Xbox.
3) On the PS2 and Xbox, there are a few movies that have had problems playing.
4) The PS2 and Xbox have a hard time reading burned DVDs.
I'm not sure if the PS3 has this problem as well, but I think it's actually better to play Blu-Ray on a standalone player than on the PS3. Game systems are expensive and if you're going to be putting wear and tear on it, might as well wear and tear it with games rather than on movies.
This is just based on experience. I don't know if the PS3 plays Blu-ray discs well or not since I've never tried it. My cousin has a PS3, so i've seen it. Just like the PS2, the loading times are very slow, but it does deliver sweet graphics though. I don't know how well the Wii or Xbox 360 are since I've never tried those systems out. I would've gotten a Wii, but 'till this day, they're still impossible to find. So, I gave up and lost interest. By the time a Wii stops selling out, it'll probably be obsolete. It's rediculous.