Overall I'm pretty impressed with the trailer. It's incredibly light for how strong it is, and you almost don't notice it while pulling it behind you... unless you're going up a hill, then things get a little less carefree, but I guess that's to be expected from any trailer.
It's hard to tell from the photos provided, but there's no solid support platform underneath the bottom of the trailer. It's basically a rectangular frame with rounded corners, and the bed of the trailer is nothing but a waterproof nylon-ish fabric stretched tight between the left and right side of the frame, which is more than strong enough for normal use. Even loaded down with 40 pounds of stuff, the bottom barely sags.
Luckily the main part of the trailer comes assembled, and all that's left is to connect the side supports, bike attachment arm, and wheels, and you're ready to go. It took me less than 20 minutes to unpack and build the first time.
Flattening the trailer for storage is just as easy. The wheels pop on and off with no tools or fuss; the side supports take a little more wiggling but nothing too difficult.
My only quibble with the trailer is that the attachment hitch didn't fit on my bike, and I had to order a special one:
Burley Bicycle Trailer Hitch (Classic). My bicycle is a fairly new steel frame road bike, and I felt it was a little weird that they'd package the trailer with a hitch that isn't universal. Plus it's frustrating getting a new toy and not being able to play with it right away.
The trailer comes with red and white reflectors, but considering how low profile it is I'd recommend getting flashing rear lights and/or a safety flag. Drivers aren't expecting you to be towing anything, and I've had one too many close calls with cars that try to change lanes right behind me.