Yeah for sure, these side quests have HUGE benefits. I've done a couple and while they're all pretty tough, the payoff is great. You're often getting something like 10 - 20K experience plus 30K in gold just for beating them. Definitely needed if you really want to upgrade your equipment well and get up the skill tree fast.
Also, I can confirm that
you can copy saves to a USB stick or other memory card if you have a fat 60gig PS3.
And here are some more screens taken with the in-game screenshot maker. All of them except the last one are from the first 2 hours of the game, so no huge spoilers.
BTW, when you all get the game, look for my pawn! Since I was able to get it early, it's currently ranked #1 overall on PS3, heh. You can see my pawn in the hydra screenshot, his name is Edgemaster (after the Soulcalibur character)