I recently bought one of these and thought I would give you my thoughts on the beast. It is heavy but saying so is perfectly balanced when in use. It is 54V 9.0AH supplied with two batteries and a charger. The batteries last a good time on each charge but being Li-ion they suddenly stop as opposed to a gradual slowing. So saying I get a bit more use by pausing for 10 secs or so before the walk to get the other battery. Yes they are pricey. (Around £500) I have been using 115mm discs but it takes up to 125mm ones. I tend to use it without the guard as it gives me more flexibility and access(I know its naughty but life is boring without a bit of danger!)