I think perhaps people have been very generous with their reviews. The pump is the smallest I have ever come across. It has no crap collecting sponge so is likely to block quickly. But in bright (direct) sunshine it does pump water quite well. Sadly the panel is only just capable of providing enough juice so as soon as even a slight bit of cloud goes across, the pump stops and just spasms every couple of seconds. As this is the 1.8W model and not one of the lower cheaper varients (not that they look any different) I am disappointed that the performance isn't a bit more consistent.
I am also not impressed with the note in the box of a discount bribe for a five star review. Reviews are there to help Amazon customers choose between the wheat and the chaff. Contamination of the review system with FAKE reviews is ruining the Amazon experience and has prompted me of late to start going back to bricks and mortar shops more often.