hi nicole,
avent stuff is great in my opinion, I use the manual pump myself, but due to my working in a pharmacy have done lots of training on the avent iq system which seems really good, they even make a double one now!
they are also good about replacing parts or going thru with you the instructions if u have any probs, i think there is a 1800 number on the boxes or they have a website where you could check out their stuff too.
another option would be hiring one from a pharmacy, i dont think they do the avent ones but then you could see how you go with electric pumping before splurging the cash on the one you want.
HTH.
XXX