I have a tilt deck trailer, wood deck, brakes on both axles, dove tail, 18 ft. I replaced the deck wood last year for the first time, but I have had the trailer for 16 years, so I cant complain about that. I am real easy on the trailer however, dont use it as much as I should...
My only thing I would change is I got the low profile trailer, so I drag in a LOT of spots...
Metal trailer are tough, better for hauling hulks as has been stated, but get real hot/cold when having to hook up your rig, and are heavy...
Edit* Mine is C channel, but with a tilt deck, its kinda like having 2 channels...