I use a hop blocker and have a lot of success with it. As Denny pointed out, I typical whirlpool and then slowly drain the kettle. You may want to try slowing your drain speed and see if that helps any.Slow drain is by far the biggest difference maker in my opinion. It takes about five minutes for me to pull 5.5 gallons.
Getting all the break and hop material in the fermenter might not be a huge deal quality wise, but that extra 1/4 gallon makes a difference when fermenting 5.5 in a 6 gallon fermenter. There is also the added benefit of getting less garbage in my repitches.
+1 - I've been using a hopblocker for ~3 years now - I really like it, but you have to use it properly - throttled back when running off, and throttled back even more after pulling up the screen. added benefit of a bit more efficient cooling for me though.
I just made a DIPA 2 weeks ago with over 24 ounces in the kettle and had only about a quart or so of liquid plus a ton of hop/break sludge left.