Since I have posted this I have actually done some more research on the pros and cons on fiberglass vs. concrete and realized that it really just depends on your wants/needs/situation. I guess I had been under the impression that fiberglass was the easier/cheaper route, and thereby less permanent.
However, you can replaster a concrete pool, but what happens when the fiberglass pool reaches the end of its lifespan? Can they be repaired, or just simply replaced? Maybe I'm wrong, but replacing sounds like a huge hassle because you would have to pull the whole shell out, and in order to drop a new one in you would need to find one exactly the same, or tear up the concrete deck surrounding it to drop in the new one. It seems that replastering your concrete pool might be cheaper and easier than ripping the old fiberglass pool out and then needing to replace your decking, landscaping and whatever else?