Review: MEC bike trailer

What is it?
MEC Single Child Trailer
How does it work?
You attach a small (included) hitch to your rear axle & the trailer hooks onto that. The child is strapped into the seat with a five-point harness. There are add-ons you can buy to make it a stroller (either jogging or regular).
Safety
The harness is pretty sturdy & padded, there are multiple places to attach rear lights, the bumpers & roll cage seem pretty solid, plus there is reflective material to make it more visible. The trailer hitch has some articulation to allow for tight turns & it will not flip if the bike falls over, unlike some trailers I've seen that attach to the bike's seat post. There is a mesh screen on the front opening of the trailer to keep debris & bugs from hitting the passenger, as well as a clear plastic layer that can be rolled down if it's raining or cold.

In stroller mode at Van Dusen Gardens

Size & cargo capacity
The trailer carries a good amount of cargo in addition to the child, which is pretty easy to access through the back hatch. There are also a couple of pockets just inside the hatch to help organize stuff--we use them for tools & drink bottles.
The single trailer is about the size of a wheelchair, so it does fit into most places we've gone, but it's a lot bigger than most strollers, so we avoid using it in stores. It's been great at big, open places like Van Dusen Gardens, where I can just lock my bike out front, then use the trailer as a stroller inside. We use it for shopping trips at farmers markets sometimes because it holds so much stuff. 
This trailer doesn't really fold up much & though you can remove the quick-release wheels to make it slightly narrower, it'd still be pretty big to store in an apartment. 
The ride
I find the trailer tracks well & rolls quite smoothly. I don't notice too much drag when I'm riding (except when going over speed humps) & it doesn't affect cornering, really. I think the ride is fairly smooth for Sprout & he seems to like riding in there. When he falls asleep, however, his head tilts forward or sideways at an alarming angle. I'm not sure if any other trailers out there have solved this problem--I suspect that if you've got a big helmet on them, they'll always flop over.
Accessories & options
You can buy an extra hitch to attach to another bike for only about $11. It's not super easy to detach the trailer from the hitch & I always find it a bit awkward to get the tow arm off when I convert it to a stroller.
We actually bought the double, initially, as we thought more cargo space & the possibility of bringing a friend with Sprout might come up, but the double is SO WIDE that you can't take it anywhere as a stroller, so we exchanged it for the single. Gotta love MEC's bomb-proof guarantee.
The bottom line
The single child trailer sells for $299 at Mountain Equipment Coop, of course, in stores or online (in Canada only). This trailer has a good set of features for the money. But I'd say if you're only planning to do a little recreational seawall type riding with your kid, you'd be better off with a front child seat like the iBert. However, if you want to do longer trips & use your bike instead of a car for things like travelling & shopping, the trailer could be a good option for you.

*I was not compensated for writing this review--we bought the trailer last year.