Mike... I had my liner pool replaced with a fiberglass pool about 5-6 years ago just before I retired. The pool install was amazing by a company in business for 30 years. They even made the shell from molds that they started business with. All employes were related to the family business for years. They had the ground dug up, the pool filled and back filled and pump running the first day of the build. The concrete work was done about 3 weeks later. I then installed my heat pump (Ohio) and fence myself.
The cons
1. I have well water so I have to think and have a plan to control metals in the pool. The metal stains will show up more in a fiberglass pool. It is something I have learned to deal with and is by no means a problem.
2. I think size restriction and shape might be a con also but it sounds like you have thought about that and have seen what is available
3. fading over the years. The pools I saw that were 30 years old were fading But you would probably get this with anything.
These are the only cons I can think of.
Pros
1. As said before very little brushing.
2. Pool stays supper clean.
3. No liners or plaster to replace.
4. Ease of quick install.
I probably could go on and on with the pros. The best thing I can say if I needed a new pool it would be fiberglass.
Mike take the day off of work if you can so you can watch the install If it is a good crew it is something special to see.
Have fun with the new pool and I think you made a great decision. I hope your pool brings the great family time for you as it has for my children, grand children, and half of the clearfork valley school system.
Ric