Yesterday I took a load of stuff 60 miles down the road to put in storage. Maybe 500-750lbs of stuff, so let's say the trailer was a little above 2000lbs. It was the first real trip for the trailer of any length.
According to my math, I got about 9.2 mpg (normal is around 20). Ouch. That said, I had to do about 80+ miles at 65mpg (had to be on the freeway with a speed limit of 75, didn't feel comfortable going 55 on it). Hopefully, when I can average 55mpg I'll get a little better mileage out of it. The good news is it felt completely stable at that speed (and even the couple of times it drifted up to 70).
The brakes did a great job. I even had to dial down the power setting once they got warmed up because the trailer was yanking on my tacoma pretty good. I don't regret the money or time spent on those one little bit.