Intereting posts about pushers there.
Alan has relaly knocked the nail on the head in terms of there are soooo many different things that make a pusher more effective than another. Not juts down to power and batteries, the scoop, wheel sizes, gearing, and grippy wheels etc. But also down to gearing and your wheels diameter depends on your batteries also. Kitty used to run on 21.6v on gold motors, but we geared her differently so shes faster as kitty dont have a scoop etc to push, so no need for pushing power, just to run around and ram the blade into people. So many litle things you need to think about depending on which batteries to get.

Mr Stu