I'm looking at extractors and have seen some that have a top crank that follows the top periphery of the tank and others with a side crank and shaft that extends to a planetary gear in the center. Do any of you have a preference? Without any experience, my assumption would be the side crank is a more natural motion while allowing a better view into the tank. Maybe the differences are minimal and I should focus on getting a good value regardless of the design. Thanks!