I have a Bri-Mar 7x12 low profile trailer. I love it and it's the only thing I have that dumps. Does double duty as the tractor hauler and hauls the Z rider for fall cleanups too...ground up leaves in front and mower in back. The low loading height is a real plus for me since I work solo most of the time....I can lift pretty heavy stuff up to my knees (trailer height). I have the pull-out equpment ramps which I will use to slide heavy stuff into the dump bed too. The only problem is the amount of room needed to manuever it ....can't always put the front end of the truck where I'd need to...not the rig you want if you need to get materials into back yards a lot. I also like that I can haul 3.5 tons/8 yards with my Silverado 2500HD. I'd need a pretty good sized dump truck to get that kind of load capacity. Another plus is that I used to sub out brush chipping on jobs where I generated a lot of it. I can get a LOT of brush on that trailer if I break it down a bit so now I keep that revenue in-house.
FYI, I do mostly maintenance and softscape. If I did more hardscape I'd probably want a dump truck.