First long ride report, 500 miles.
It is almost true that you do not know the trailer is behind you.
At highway speeds you can't tell at all. No impact on the cornering or riding character of the bike at all.
At low speeds you can tell it is there more. You feel the trailer bounce a bit when it goes over a bump. My light trailer, empty, would bounce around quite a bit. When I added the weight of the soda, the bouncing decreased. The bouncing does not bother the ride, or make it unsafe, you just sort of feel it bounce is all. You also will occasionally hear the rattle of the chains, or the some other odd noise from it.
Backing a trailer is not second nature. If you have never done it, be prepared to make a few mistakes that you have to pull forward from to correct. It happens. Practice doing it when there are no obstacles around.
Definately be aware of the extra weight behind you. Brake sooner, be prepared to accelerate just a tad bit slower, etc... nothing major, just don't forget about it.
All that being said, I do not regret the trailer at all. It will come in very handy indeed on countless occasions.