Jake, I can't add much to what Mark and Mike have said.  My brother has had a Trinity for a number of years.  It has not had cracks in the frame.  We've seen serious suspension problems on a couple of triple axle Trinity's we've seen.  Also, if the liner is not tight, moisture and crud will rust out the sidewalls and bottom.  That problem probably is worse in your area than it is in the arid west, but that is probably a problem with all makes.

I bought a 2000 model Trinity in June.  Trinity's claim to fame is the lightweight design of the trailer.  Here is a link to a page on their site where it tells about the light weight and strength.  If you are going to be hauling on heavily regulated roads, the Trinity may be the way to go.  I think Trinity, Red River and Alick all make a good trailer but all will show abuse with time.