How would you group different makes by price point/quality?

You got some good advice right away. Listen to what LouLou said about the frame. First you are buying a trailer, so get the best running gear and frame you can find, then look at the fancy stuff in the box.
Compare axle sizes, tire sizes and number of lug nuts. Check the size of the brakes. Axles are rated in the lbs they can supposedly carry, but go for overkill. Most use the bare minimum and call it light weight, but I call it cheap.