Shop around! We got all new windows 5 yrs ago and we love them. We interviewed several window contractors and went with a company that developed a product that's not exactly wood, but not vinyl either. Some composite that looks better than vinyl, but doesn't 'weather' like wood.
Anyway, talk to different companies. Check out what materials they use, their guarantees, their installers, etc.
Good luck.
* A woman is like a tea bag. You can't tell how strong she is until you put her in hot water. *
- Eleanor Roosevelt