Open trailers all the way. Versatility, ease of access, visibility/safety, cost, and rebuildability. Ever try to rebuild an enclosed trailer? Only pluses I can think of for an enclosed are, security for your handhelds, and hiding whats in the trailer (and how well its tied down) from the DOT. Rolling billboard can be a plus or minus depending on your situation. Keeping your equipment dry without unloading is another one. Its a personal preference thing I guess.