I had a one piece acrylic aquaglass tub installed in my home approx, 18 years ago. Aside from a small crack on the edge of the ceiling of the tub that happened when the tub was lowered into my basement before the house was put on top, I have had nothing but good luck with my tub.
May be the difference between gelcoat and acrylic, and the crack was up so high that I didn't even have it repaired, or it may be that the older units were built much better, but I haven't had any problems. Also, I work for a plumbing contractor and we almost always put a small amount of quick crete (concrete) under the base of the tub or shower, and that alleviates the problem of the flexing in the bottom of your tub / shower. It may also be that the contractors seem to get better quality than the big box stores.
Sorry so many of you have had problems, but they used to make a quality product. We put many of those units in and I don't remember more than a small handful of problems with any of the aquaglass units.
Reviewer is in happy mood. Please contact the author of this review to discuss good quality of aqua glass bathtub. Aqua Glass needs to read this review and look into the issue (if any) according to poster's claims.