I looked at the BigTex trailer website. Probably more expensive than I want to know. I see lots of dentists driving to their hunting lease with 4-wheelers on BigTex trailers. Seriously, I think they're a pretty solid trailer. If you're going to buy off the shelf, BigTex isn't bad.
I haven't had any problems pulling mine. I've carried up to 4,500 pounds and it never swings. I did build it with the axle farther back than most. Looks weird but rides better. Backing up with skinny trailer is a hassle. It kicks out quickly and is tough to see. Not a real big deal though.
The bolted-on jack? That's cheap and crappy.
From the photos, it appears the jack doesn't even have a footing. It's just a tube. That means it will sink in dirt and mud. If you get any rain, you can bury it to the frame. Terrible design. Unless you're parking on concrete only, you gotta fix this.
You see the little triangle, where the jack attaches to frame? Flimsy and basically worthless. It has no strength whatsoever. It's designed to keep jack in position. But that's a fantasyland. If you ever disconnect your trailer with any load, trailer will move a little. Same story with hooking up to trailer hitch. Even wind will move a empty trailer around. First time your trailer rolls, it will crack this spot-welded triangle. Second time, it will break.
Solve both jack problems with a stout disconnect Bulldog jack. Just weld it to the frame. Can't think of the style name, but you can fold up the jack easily. Much stouter jack, much stouter mount, and much better footing.
And it is EASIER to work with. A bolted on jack must be cranked all the way up before driving. My reccomended jack (somebody help me with name) just needs to be cranked enough to clear the ground, then you take it off with kotter pin.
Trailer lights - I'd look for some that were welded onto the top of frame, not the bottom. You're going to break lots more lights when they're low. I also like a cage around lights.
Another thing to think about are the sides. I put expanded metal on the sides on my trailer. It keeps stuff from rolling or flying out.
Also look for cleats or places to attach rope. Should be on the frame, not the brackets. If it doesn't include them, you can weld a few on there for about $5. Really helps out.
Depends on what you're hauling, but I'd look around some more. A few minor adjustments can be made cheaply.