A mouse is one of those few components that you need to put your hands on.
You don't mind paying $10 for a half decent mouse, but one day you will replace it. When you do, then consider this good, middle of the range, mouse.
You get a mouse that sits well in your hand, the buttons are positive and it's not too heavy and not too light. (Heck you could eat it for breakfast then!)
I don't use the side-scroll feature much, but if you use spreadsheets and navigate large graphic areas, then it will make life easier for you. If you need to spend $50 on a mouse, make it this one, you won't be disappointed.