Trailer is a net negative weight wise, and a net positive handling wise. So it depends on which of those two is more of a concern for you. I was always more concerned about extra weight on downhills than uphills; make sure your brakes are rock solid. That's true either way, but even more so with extra weight.
When my stoker wanted to have an easy day, the deal was she could take it easy except when I called for help on the uphills. Worked well for us.