Panniers vs trailers. One of the great cycling debates. People travel the world over with each so they both must work. some people convert from panniers to trailer, others from trailer to panniers. What's a poor cycletourist to do?
Someone expresses concern that trailers have more moving parts to break. Yet panniers are not without their failures. The bags can tear, the attachments can break, and I have read numerous journals where racks and screws break.
Handling is bad on trailers, but poorly loaded panniers can cause dangerous shimmy. In either case, any bike with 50+ lbs of dead weight is going to ride like a drunken hippo.
I'm a BOB user. I got the BOB to pull behind a mountain bike on the rough, rocky backcountry roads at Big Bend National Park. I've had great luck with the trailer. It's very stable and doesn't give me any problem. My trailer does not have the rear suspension, yet it does fine bouncing along behind me.