We've got three different bike trailers, and they're used in different ways. All three of them have been used in the last few days and I think all three are worth a few words.
Our oldest is the BOB Yak trailer. In the early 1990s when we lived in Cambridge I read on the HPV (Human Powered Vehicle) mailing list about the newly introduced BOB Yak single wheel trailer. Much to my surprise, a few weeks later when I visited my parents in Somerset, their local bike shop happened to have a BOB Yak before any had been officially imported to the UK. It had been left behind by an American cycle tourist who passed through the area and sold his equipment before returning home. That's how I came to have one of the very first BOB trailers in the UK. Thirteen years later we still have that trailer and it's still used regularly.
It has its limitations. You can only transport relatively light loads, up to thirty kg or so. Load it up too heavy and you will have a hard time keeping the bike upright. Put too much weight on before heading down a steep hill and you discover there is a speed at which it starts steering you rather than the other way around. Because it's a single wheel trailer it's not the best choice for shopping because it doesn't support itself, and of course if you want to carry children or pets, you need to look elsewhere. However used for what it excels at, fair distances and speeds, and it's wonderful. A single wheel trailer never tips when you corner. I find the BOB works excellently with recumbent bikes.
I make a basket especially to fit the trailer, which means you can simply sling stuff in instead of having to muck about with zips.
The BOB Yak and Ibex trailers are currently available with a special offer from the bike trailer shop.
The photo shows the trailer in use on Tuesday when I took it to Groningen with me and returned with a roll of packaging. A light load, but not an especially aerodynamic one. A while ago I made a blog post including a video showing the trailer in use. More trailer posts to come...