Check into what sort of pool you need for your area babe...
We have a fibreglass, the IL's have a concrete...

Heating our pool is fast, so much much cheaper.
Concrete pools are MUCH colder, so if you'll use the heating a fair bit, its going to be very exxy to run... We have had our heating off since Oct, the
Il's are still using theirs cause the pool is still way too cold. And we have a pretty warm summer here! The fibreglas means we use it more of the year than the IL's too....

So if you live in a really hot spot, concrete would be better for heating and having a colder pool to escape the heat. If your area is only average to warm, a fibreglass would suit you much more.
What size pool is yours compared to your IL's? Do you guys have shade sail? We have a fibreglass pool, with shade sail and solar heating. Our pool is approx 9 x 4.5 in size and the shadesail covers about 90% of the pool and between Oct - Mar we don't need our solar on at all. So for us up here in Cairns, a fibreglass is perfect.