Fiberglass goes in much quicker. Your limited on size and depth though because it has to be able to be shipped on a truck and be legal on the road. Has to be set with a crane so keep that in mind on timing. Fiberglass can crack, have a hole punched in it, or even break, so they aren’t 100% maintenance free. A friend of mine has one that currently has a break in the middle. He had to have it repaired but it still has a spring to it. I expect him to fill it in, in the future. I have put in two liner pools. Shape and depth are limited to your imagination. Liners have come a long ways and some advertise lasting up to 15 years. I have a friend that got 12 years out of one. So if you put one in now, then 12 years from now, have to do it again, realistically, that’s probably the only time you’ll have to do it because most of us will be “on the other side” by the time it came around again.
Liners can rip but are pretty durable. More so than you’d think. I’ve been happy with both of ours. Liner pools take much longer to put in. If you don’t time it right, you’ll spend all season having it installed only to end up being too cold to use it until next season. Whatever you decide, salt water is the way to go. Everyone that complains about how much chemicals cost, how much work they are, etc…either doesn’t have a pool, or hasn’t been around one since the inception of salt water. I’ll be getting mine up and running this week and won’t have to do anything to it but vacuum it manually, about once a month because I have a vacuum that comes on automatically every morning. I’ll test the water weekly but have never had to do anything during the season, after I get it all set. Don’t waste your money on a heater. They take too long to heat the water and cost a fortune to run. Good luck and enjoy! We love ours. We use it more and more every season.
