Design
The Croozer Double sits lower and wider than most other trailers, which adds stability but also makes tight squeezes that much tighter. (It also means it’s even more important to use the flag for visibility.) It’s burly: two big aluminum bumpers protect the front and sides, and the five-point seatbelts are anchored to the frame. Minor complaints: things inside tend to slide back under the seat, and it’s hard to find a lock point if you want to secure it with a cable. On the plus side, the luggage space behind the seats is huge.

Performance
As a trailer, the Croozer’s bike connector arm is moderately springy when you’re pedaling. The axle hitch and connector arm could both use some redesign: the hitch is hard to connect, with a square plastic collar that keeps slipping off, and the connector arm has a tendency to rattle when you’re riding. Even worse is the adapter for the jogging front wheel: each side arm is a separate piece, and the part where the wheel axle attaches is plastic, making the whole thing so wobbly it’s basically useless. Taken together with the tiny plastic stroller tires, that makes the Croozer really just a trailer that you can use as a stroller—in a pinch.
 
Comfort
My patient reviewers gave the Croozer Double two thumbs up for comfort. It’s roomy inside, with a low center of gravity, and its wide bucket seats are in a more reclined position that makes it easy to drift off to sleep.

Convenience
All the removable external pieces—wheels, arms, etc—fit inside when the trailer is folded up, and there’s a clip to keep it folded, making it easy to store. It’s heavy and awkward to carry folded up, though, without a carry handle. And it’s tough to fold and unfold, maybe because the nylon cover is tight; there was definitely some grumbling during the first few attempts to click it open and fold it up.

Quality
Aside from the jogging and trailer-attachment accessories (see above), the Croozer Double itself is well built.

Value
Unlike some other models, the Croozer Double comes with everything you need to make it a bike trailer or a stroller (jogging or regular). It even comes with two axle hitches, and the convertible insect/rain cover is built in—no extra doodads to buy.