I've been to the JHBH in DC and wasn't very impressed, but the location right by the mythic Harvard is a much better pub. Showed up right when they opened after touring (lurking about, actually) the campus. The bartender was chatty and beer knowledgable, providing great conversation to go along with the samples.
The Demon DPA (Double Pale Ale) was a very well brewed pale ale--clean and hoppy with a resiny spine to hold it together--to compliment the rest of the line up, including one cask. Surprisingly, the Harvard Square Helles was my next favorite, in spite of not being fan of the style in general. Very clean and balanced beer that I'm sure is popular with students; however, it's nothing to shy away from as a beer geek. Always a good sign when a pub can do a light beer so clean. I didn't check out the eats in order to save room for a more vegetarian friendly restaurant later in the day.
Overall, a surprisingly pleasant stop.