I've got the 20' Big Tex 10PI 10,000# pipe trailer and am pleased with it so far. However, if I had to do it again, I wouldn't go the pipe trailer route....too confining. Loading & unloading have to be done very carefully to avoid scraping paint off everything. And you can't have any overhang anywhere.
Mine has the built in, fold down ramp gate in the back. It's a bit shorter than normal ramps would be so the load/unload angle is steeper. The gate also adds a fair amount of weight to the back that tends to make the trailer a bit tongue light when empty. When dead-heading I usually throw a sandbag or two on the front of the trailer for a better ride.
My trailer is going on 2 years old and the deck planking will probably need replacement by the time it reaches 5 years. Haven't seen any rot yet, but it's gotten that 'weathered look' rather quickly.
But those are the negatives. On the whole it's a good, tough, reliable trailer that looks good too. Up here the Mennonites seem to like them.
Bob