I personally never had success with any pump. I never tried the electrical ones (I've heard Medela is the best) because I just couldn't afford to spend that much money. I got a couple different hand pumps, First Years $30 (terrible) and Avent $60 (more comfortable but didn't really work for me), but I could never get more than 2 oz at a time and it took about 30 minutes and a very sore hand and nipples to get that much! I just gave up pumping and decided if there was a time I couldn't nurse my children could take a bottle of formula those occasions. I've got some friends that could get tons of milk with the electric pumps and hospital grade ones that they rented, but I personally think breast anatomy may have something to do with how well a pump works on each individual or something. I would just advise if you are going to buy a pump to spring for the more expensive ones--I wasted money on the cheaper brands and always wonder if I should have just bought the Medela after all. Good luck with it!
~B.