I've ridden 7300 miles in the last year with a burley nomad trailer in addition to panniers. Before the trip, I was worried about tipping the trailer, getting it caught on obstructions, or being too wide for narrow shoulders. It turns out my Ortlieb panniers on a wide, disc-brake compatible rack are actually slightly wider then the trailer. The trailer, however, appears wider and more visible, so vehicles tend to give me a lot of space. The long trailer arm dampens the jolt of potholes, rocks, and minor curb-bumps. Unless you're hitting something pretty big, pretty hard, it doesn't 'pull' on the bike. It's also easier on your bike, since the main weight load is centered over the trailer axle.

The primary downsides to the trailer are the addition of two more tires which may be punctured, and more hassle trying to get a ride or take a bus. I almost exclusively wild camp, and a few times I've had to pass up on nice spots because I didn't want to haul the trailer over a crash barricade or through thick brush. It also means I have more bright, yellow surface area to camouflage.