hi jenny, i bought the avent electric one (and used the bottles that came with the avent microwave steriliser).
when i first used it, i found it difficult but once i got the hang of it, i remember thinking, thank god i got the electric one because there's no way i could hand pump this.
BUT... now i use the pump manually (it converts) and actually i find this SO much easier. Once you've mastered it, you don't really have to pump continually, you can pump and not release for a while and the milk just flows - is unbelievable how your boobs spurt milk so!
just remember to drink LOADS of water and keep eating so you produce enough milk. i found i tended to exhaust my supply a bit as you kind of need the milk you express for later, for the next feed...
Also, take it easy, rest loads. This really does make a difference.
I'm still B/F at 5 1/2 months but i won't pretend it's all been plain sailing. Hope my advice will help you!