Foam is cheap (money wise) and can look cheap, but it can be great if you put time and effort into it. Foam and fiberglass are just two different methods for people to choose from, and which you choose is really just up to which you prefer, or find easier to work with. 405th is stock full of tutorials on the pepakura/fiberglass method, but since foam is rather new, I'm afraid I can't really point you to any specific tutorials, since tutorials on foam really haven't been done yet. Definitely check out Nick Nack Patty Wack's thread on his foam build, check out drack's work too. They have some of the best foam suits so far. If you choose to go with pepakura, there are plenty of stickies in the various build sub-forums. Goodluck.