Sorry you didn't get any replies...I was hoping someone would chime in. Are you using it on a Blichmann?
I have the Hopstopper too, but I haven't used it with a pump yet. I just got my pump the other day. I originally used it on 10G Blichmann and IC...fail...cold break clogged it. I then used it 3 times with a CFC gravity drain on the 10G and the flow was very slow, but worked. I then used it on a 20G blichmann with gravity drain through a CFC and the flow was incredibly slow filling the second carboy. I ended up giving up and lost about 2G of wort...I was thinking it was the lack of height from the BK to chiller to carboy, but it might've been the hopstopper.
As far as cleaning, I didn't have too many issues. I used the sprayer on my kitchen faucet to knock most of the big hop chunks out, then left it in my BK for a PBW soak. There's a little bit of debris still there, but I'm not too concerned considering it's part of the boil.