to get it now would be a horrible idea. If you made it this far past the holiday season without a PS3 i say wait until the next inevitable price drop in 2009. those games arent going anywhere. Except maybe down in price....just wait dude.
I love steam. for the longest time I thought it would be the online service I would us to buy my games. then when blizzard opened up their digital store I thought hmm okay well it will only be blizzard games there so I'l use that for my blizz games. Then Good old Games went into closed beta....Wow this looks pretty good. once they went on open I finally decided to buy a game and was totally happy with it. Now im debating if I should by oddworld on steam or gog. Im leaning more towards gog because of the free extras you get when u buy a game. plus the no DRM stuff is awesome too.
Expert is not that hard. you just gotta watch the FF thats mostly what messes us up. As long as you know how to deal with the tank and witches on expert its fine. Of course I play on PC so quickly scanning your surroundings is alot easier and faster I guess that might help making expert less frustrating and more of a challenge of teamwork.
Also, Never PUG. Make some friends on STEAM/XBLA or play with people you know form the forums. It's alot better then dealing with trigger happy random people.