A long time ago, in a galaxy far far away...
The PS2 came out, at the time it was great, but currently it is the least capable of all systems on the market.
That being said, I love my PS2, and all I play (for now) is Starwars Battlefront. The best part of Battlefront, is indeed, the online aspect.
Highpoints for PS2 online: team play (you can find some great players out there), voice chat, large number of online players (we don't have halo2 to suck all the good gamers away from the servers)... really it comes down to your team mates and opposition make the difference between a good or bad game, the exact same battle map can be played so many different ways. Having the access to install a PS2 SWBF server on your PC is a nice option as well.
Lowpoints for PS2 online: occasional lag, lower resolution (compared to Xbox and PC), weak team members (including team killers) and the occasional issue with gamespy (used to find servers and keep track of your stats).
It is a good game offline, but an even better game online. If you get lucky and find some good team members, you are in for some awesome battles.