We have an 06 Sportsmen (2604) and love it. It is aluminum sided. Very well built camper. 10,000 gvwr, plus 5300# axles, which is kind of unusual.
Has a lot of standard features that are options on normal trailers.
Weight wise, they are a little heavier than other campers of their size. Tons of storage inside and out. Black water rinse, hot water bypass, lots of little extras that most people add later on.
Most important part of fiberglass is keeping it sealed up. When you get it, either stay on it with the self leveling sealant, or get some 4" wide eternabond tape and seal it up good and tight. Delamination is what you want to avoid.
Richard White
2011 F150 Ecoboost SCREW 145" 4x4
Firestone Ride-Rite Air Springs/Air Lift Wireless Controller
2006 Sportsmen by KZ 2604P (30')
Hensley Arrow