I agree about the heat and the hills, it was pretty tough out there!
I couldn't get a signal on my garmin so did the first 5 miles way too fast (had no idea what speed I was going and everyone else was going dead fast!) so I was pretty much holding on by my fingernails from mile 9.
Anyway, I was very happy to finish in 3:35:02, especially as I failed to start Boston last year due to a slipped disc (and it took me an hour to walk last year's B.A.A 5k.)
12 months ago I was having surgery so I can't complain.that it wasn't a pb!