This is my favorite US Post Office; the lines may get long but they actually move pretty quickly and now they have a machine in the lobby where you can mail packages (and buy stamps) and not wait in as long of a line. The only thing is, be careful when you buy stamps from this machine....they don't always come out and you'll end up having to wait in the line you wanted to avoid if the stamps get stuck (I have seen it happen twice to people in front of me; in one case I could help the guy because I was printing something and his last stamp came out with what I printed).
The customer service here is stellar - I adore the clerks, they are all generally incredibly friendly. Maybe one of the older lady clerks isn't as open but she is still friendly. Almost every time I've been in, I have a brief, small, chat with the clerks...nothing to hold up the line.
Appreciate this type of customer service at my neighborhood post office!