First you have to match the tow vehicle's ratings. What is the max cargo? This is usually found on a door jamb sticker.
Max cargo includes the trailer tongue weight, people and stuff and is often the limiting factor in trailer selection.
The majority of the trailer are built to various price points, you get what you pay for. Some models, such as Airstream, Lance, Bigfoot, Casita and others have unique features and hence command a higher price.
Dry weight means little, gross weight is the number to consider.
I always suggest renting a unit similar to what you think you want. A week or so on the road will tell you a lot.