I am considering to go to a fiber glass slide in camper. Are they better than a aluminum camper, What are the pros and cons to this?

 

Good question. My experiences after owning motorhomes, trailers and slide ins. Aluminum - - usually used on wood framed rigs - - not as desirable as aluminum framing. If it is the strip aluminum, not sheet, I would not opt for it. It is much harder to keep the corners, vents, windows, etc sealed over time. When they leak, they rot out the wood - - not fun. If it sheet aluminum, it will dent and scratch easier than fibreglass and it not easily repaired if punctured.
Fibreglass - - harder to scratch and dent, easily repaired, somewhat heavier, many FG units are aluminum framed. And, be sure to opt for gel coat finish. And, as with sheet aluminum, much easier to keep corners and openings sealed.
Bob