Help me decide: Owner-Builder vs. GC

[Grace Simpson]

This is my first project that I'm doing on my own - 425sf addition + upgrading existing house. Permits are at the final stage and I need to decide on a contractor. I've checked references and visited their work on other homes but am still agonizing over this decision.

My choices (all were referrals and all are very nice people):
1. Expensive GC who I have confidence in but I'd rather not spend the extra $ unless it's highly advisable.
2. Less expensive (smaller) GC with mixed references. I'm not thrilled with work I've seen but I think that is b/c the homeowners chose cheap materials.
3. A very experienced sub with good-looking work. In this case, it would make sense for me to get the permit as an owner-builder and I'd save $, but I'm inexperienced. 

I have a close friend who has been advising me but has been out of the country for a few weeks. Advice appreciated!