Hi, just to share my 2cents worth.
I also feed my boy EBM fully until he turned 1 yr 'cos he doesn't latch on at all. Used the Avent pump all the time,
Disadv: takes more time to finish both breasts (total 20-30 minutes)
Adv: extremely portable and quiet. I travel quite a bit for work, bringing it with me (along with a small sterilizer) overseas is a breeze.
But the valve popping out is indeed a problem, takes some getting used to and the other trick is also to change the valve quite regularly.
Any qn just call Avent @ 6391 9191 and they will advise you on what to do.
Recept is very friendly and knowledgable.
Btw, if your pump body break, you can also buy replacements parts at their office located at Gateway building (near Bugis).
Their after sales service is very good...