Lil Shark works pretty darn good
We use the Lil Shark on our AG and it works pretty darn good. The one thing that we did however, is place a leaf canister in between the shark hose and the intake, eliminating the extra cleaning at the skimmer. It does a very nice job getting the whole pool clean and rarely hangs on anything. I believe it only has the one moving part.
Polaris 180 vs. Cleaning Head
We have a Polaris 180 which works off of a booster pump. It works adequately well, but since it cleans to a mesh bag, it is really just driving around stirring debris. It will pick up anything larger than say 1/16" square.
The absolute BEST thing that I have found for cleaning the pool quickly is the 14" RB214 vacuum head that Ben sells for $75 at
PoolSolutions.com....http://www.poolsolutions.com/cart/clean.php
I know it sounds like I drank Ben's Kool-Aid, but this thing works great. It is heavy and steerable so you can vacuum the whole pool in about 15 minutes. Since I bought his vacuum head, I vacuum the pool on Saturday mornings for a few minutes. I actually have become obsessed with how clean it gets the pool.
I am ashamed to admit it, but now I really do just use the Polaris 180 to stir the pool when I add chemicals.
This is no joke. Don't buy any automatic cleaner till you try this head for your vacuum. Make sure the filter is clean too so you have good suction. This thing really works and works quickly. It is obviously a professional grade device that you wont find at your local store of the same quality.