Both make fine shells.
More importantly, compare the installation procedures each dealer uses. Things to look for are:
1) Spoils from the dig are not used for back fill. Mason sand or 3/8" gravel are the only suitable materials as they minimize voids and settling.
2) Materials used for plumbing. Flex pipe is often their material of choice. DON'T let them. Require 100% Schedule 40 solid core pipe and fittings. Use 2" runs for the suction lines and to feed the returns, which will have 1.5" stubs connecting to the 2" run from the filter to the pool for an energy efficient water path.
3) A sump or dry well is installed. This is to de-water the area under and around the shell should it need to be emptied or lowered. Water under the shell will make a boat of your pool when the water table around it is elevated and the pool level is lowered.
4) If waterline tile is to be used, select a pattern with small tiles so the curves appear smoother.
5) Small (3/4 HP) pumps and larger filters pay dividends.
6) A 3' concrete collar with rebar attached to the shell helps to lock it in place.
7) Watch for clay, water table, or fill during the dig. None are a suitable bedding and should be removed. This will require an over dug hole and either 3/8" gravel or mason sand to be used to bring the level of the bottom to the proper height. A soils engineer's report is suggested if your area has a history of this type of soil before the hole is dug.
Good luck!
Scott
