I cannot speak for Jason(and I didn't read his comment as knocking AP) but, I have purchased his enclosures and one from Ricky's Reptile Enclosures and, both of these were well built items. There are other manufactures of PVC enclosures locally and some use silicone as a primary bonding agent instead of chemically welding components. A well done chemical weld is superior to a silicone used as glue from both a structural and an aesthetic standpoint.
The idea of the AP being available as RTA(ready to assemble) units strikes me as brilliant for shipping although, personally I would be inclined to use PVC solvent cement myself for assembly. But, my job required me to work in metals, plastics, wood and masonry so, I am pretty comfortable making or modifying components for enclosures and doing things a bit different than suggested.