I was working on a long-duration balloon payload (ANITA-IV), so I was in a hangar much of the time. Since it was summer, it wasn't that cold, but the constant daylight is disorienting. The isolation from the rest of the world is the hardest part, even though at McMurdo, unlike pole, there is (slow) internet all day long.
McMurdo is an interesting place with a lot of fascinating people and the scenery is very beautiful. As our balloon launched pretty quickly after we were ready to launch, I unfortunately didn't get much downtime to do all of the hiking trails and such (but on the plus side, I got to go home earlier).
If you ever get a chance to go (either as a scientist or, possibly more likely for many, as support staff), I highly recommend it.