It would be hard to comment on other fiberglass supply company's without ever dealing with them, and just as hard to comment on your choose of materials (wood/composites, resin, glass).
Many of us have got our stuff through Express, so we know there good.
Glastron's and most other boats were slapped together as fast as possible and have lasted 30, 40 and even 50 years.
As long as you use good quality resin / glass / wood and take your time to mix and laminate, your boat should last another 50 years.