In a week of touring with the trailer, I felt the tugging motion just twice, for just a few seconds at a time. I had expected to feel the tug a lot more often. Most of the time, I couldn't even tell I was pulling a trailer. When I travel with panniers, I notice a difference between the handling of a loaded bike and an unloaded bike. That difference was minimized with the trailer.
The trailer I used was a Burley Flatbed, borrowed from a friend. My experiences with it were mostly positive and I'm thinking about going with a trailer again for some future trips. But a trailer is not for all bike touring. There are some trips, particularly lightweight weekend excursions, where panniers seem like a simpler choice.