Road salt is a major concern with steel trailers in the upper mid west. If you get one, you can expect to need a ton of welding and rebuilding done on the bottom 18 inches or so. Even if they are well cared for, the salt will eat up any money you are thinking you are saving by going with a steel trailer.
That said, shop carefully and consider use/ wear that you plan to inflict. For lighter use, almost any brand will do. For heavier use, I prefer a 4 Star. The featherlights we've used just don't stand up to the beating as well. For someone hauling every day, a Wilson is a good bet. The major drawback I've found with Wilsons, is that the resale value (at least up here) sucks. This is probably because they are used by tons of livestock haulers, and most people assume the used ones for sale are beat to h*ll.
Steve, we have had a 4 Star that actually appreciated in value in the 8 years we owned it. Since we are looking at getting a new trailer soon, I feel your pain on the price!!!