I had the Avent Isis IQ one. I had bought the avent manual one and was getting on fine with it and as I was expressing all of Williams feeds - I also bought the Avent electric one too so that I could do both sides at the same time.
It was very easy to use. It was nice that you can control the rhythm of the pumping action. I have no problems with it. It wasn't the quietest but I don't think any of them are really quiet? SOmetimes if we were watching a movie - I just used it manually instead as you can still use it manually.
I was also using the Avent bottles and of course you pump straight into the bottles so I chose that one to save extra sterilising.
If you have any specific questions - please ask.