I think the bigger factor is what will you use to pull the trailer and do you want much more capacity than 2000 pounds. A 16' foot trailer can get real heavy. I would not buy a trailer built with angle except for very light duty use. Steel tubing is very strong, but is also more expensive. Steel channel has good strength to weight characteristics, and is a common material in well designed trailers. If you are only hauling 2000 pounds and the trailer is built for light duty use, then brakes on one axle is reasonable. I just switched to a trailer with brakes on both axles, and for GVW loads of over 5,000 pounds behind my 1/2 ton pickup, I really appreciate the extra braking power.