I will pretty much agree with what brian4wd says, and I'm an RV industry insider. The company I work for used to make toyhaulers (we sold that segment of our business to Weekend Warrior about a year and a half ago). I was looking into buying one when we still made them, and I was pretty familiar with our product and those of most of the major mfgs. Toyhaulers are nice in that they offer a lot of nice amenities that you don't usually find in car haulers, race trailers and converted enclosed cargo trailers. But the construction and structural integrity are what I called into question. The ones we built (Rage'n, now an independent trailer mfg owned by the owners of WW) were actually pretty good compared to the other toyhaulers out there. But the problem was that they were still TOYhaulers. They'll work fine for getting a couple of quads or 2-wheelers to the desert, but I had real reservations about subjecting my fully outfitted, trail-ready EB to one of them. Even though I could have gotten an awesome price on one with my employee discount, I still decided to instead go to a custom trailer manufacturer and have one built to my spec's. I have a build-up thread here in this forum for my Universal Trailer, check out the construction in some of the pictures in that thread and compare it to what you see when you climb under a typical toyhauler. Some toyhaulers have plenty of capacity on paper based on the axle weight ratings, but the trailer chassis, floor and sidewall construction just don't seem to be up to the task in my opinion. You didn't mention what you intend to haul in it. If it’s a typical real-world 4X4 like most of us here have, I would just make sure to take a close look at how the ones you're looking at are built. If it’s a lightweight moon buggy, you might be fine with a regular toyhauler.
Dusty