I've built a few from CLC, Pygmy and one Merganser from Shearwater
(Eric Schade).

They're only about 5lbs lighter than a fiberglass kayak if you outfit
it identically AND reinforce it for the same level of durability.
Understand there's a wide range of weights and durability for glass
boats but that's my experience.
Pygmy tends towards high volume and a good range of handling
characteristics, CLC tends towards high volume and values the building
experience with handling a second thought, the Shearwater Merganser is
a good medium volume design.

Read everything about epoxy exposure and safety,,experiment with the
goop before building. The Guillemot forum is the definitive online
resource for kayak building with a wide range of other paddling
related issues.

Issues of maintenance and durability are dependant upon use and
construction.