I have two manual pumps. One Avent and the other is The First Year. I have been using the The First Year the most. The Avent is ok but the little parts are driving me crazy. If you don't put it together the right way, it won't work. The First Year is a one piece, you don't have to take it apart and assemble it to wash it. You can rinse it easily. I just prefer the The First Year pump. I am sure some people will swear on the Avent. Wish you could try them all! lol
I also use an electric pump at work, but since I only work one day a week, I mostly use my manual pump and I am able to get just as much milk with it than with the electric.
There are some great websites to give you tips, like workandpump.com
Good luck!