Help me with current best manufacturers

I like to look at roof construction when considering the quality of a trailer. After all, the roof is your first line of defense against water intrusion which is the single largest detriment to longevity. The molded fiberglass trailers excel here and are the closest to be considered leakproof.

Check out inTech and ATC (Aluminum Trailer Company), both utilize single sheet aluminum roofs. ATC trailers are toy haulers, but their quality is high. Both utilize welded aluminum frames.