I use a homebox xxl, zero light leaks, No PVC, works great, havent had any problems. The secret jardin darkrooms are notorious for holes all around the seams and pin holes in the walls.
Also Iv seen some of the budboxes, hydrohuts, etc, Im not sure which one was recalled for using PVC that was toxic to plants, but all of them had extremely weak poles, I saw a pic of one on here and the poles were so bent from the gear hanging that they were like 6 inches from where they should be.
So far my homebox hasnt had this problem at all, I got 2 fans, 2 1000s lights with aircooled hoods, 2 carbon filters, and a shitload of ocsilating fans and shit and I could probly hang another 60lbs easy.