and nylon takes forever. Also a beginner can get frustrated with nylon because the sound will always seem muted unless you get the string firmly pressed. My wife gave it up for that exact reason. She'd be properly playing a chord but it sounded like crap. It wasn't until I switched her strings out that she kept playing.

Nylon won't hurt nearly as much so it has it's pros, but in the long run I think metal strings are the way to go