This took a couple of days to get used to, but now (about two months later) I wouldn't go back to a standard mouse. It is very comfortable and works well. I paid for this myself and the standard mouse issued by work sits in a draw. I hadn't really noticed the strain a standard mouse was putting on my forearm but switching to the E90 has really opened my eyes! The mouse is good value and quite well made. A little bonus is that using a left-handed ergonomic mouse is an excellent additional layer of security - right-handed 'normies' are flummoxed by the E90 :-) Purchase via PBT was easy and delivery was fast.