I only have an Avent, so can't help with the other.
I think it's great and it worked just fine for me. i expressed for a looong time when i went back to work.

My best advice though would be find out where you can get one from in a pinch, but don't buy it unless you need it. With DD I had terrible trouble and DH had to dash out one Saturday arvie and find one. It saved us.
BUT with DS I haven't touched it yet.....so would have been rueing the waste of money if I'd bought it specifically for him.