I can't speak to the vinyl vs. fiberglass issue, but Marvin, Milgard and Anderson are some other big names in the replacement window business. Regardless of the material or manufacturer, the quality of the installation is probably the most important factor. Make sure to use someone who does it professionally and check their references!

I started out with nothing & I've still got most of it left
M60 VP160 QS8 EP350
M22 VP100
Algonquins