Sorry bud, I forgot to check back on this.
Wells Cargos for one hold their resale far better than any other.
Second, the way they build their wall and floor sections and paint the frames are just done better than the rest. Most issues people have with steel trailers are caused by poor prep and paint at the factory. I have seen very few Cargo's with these issues.
You do have to pay more for them but, you are getting more for your money. I have not owned one so this is not biased.
Charmacs are great trailers but they use a hinge spring that makes the doors really heavy. Also the ones I have seen down have a beaver tail so the back ramp door is really steep.
Haulmarks, Interstates, Pace, etc.. are all the same quality of trailer. Mirage owners used to be with Interstate so the mirage trailers are similar. They made changes that work better for snowmobilers so I like them personally better.
If you went aluminum, there are only a couple that I would spend the money on. Featherlite is tops hands down no other trailer is in that league. The next for me would be Wells Cargos silver series. That is the trailer I would like to have but $.
This is all just my opinion so take it for what it's worth, which isnt much....