Trial and Error.
Three Weeks ago I bought a Kennsington Bluetooth Mouse to go along with the internal bluetooth in the ol Macbook.
I used it for about 15 min before I put it back in it's package and asked Liz to return it and exchange for the Apple Wireless
(which I had used before and liked, I admit it I am cheap and am always trying to find the best deal I can get).
While in San Diego I exclusivley used the Mighty Mouse and became highly addicted to the scroll ball.
The day before my return (last Wed.) Liz did the old switcher-oo and I tried using the un-tethered apple mouse but the absence of the scrool hurt too much.
Then Voila!!!! Tue. Apple released the tail-less mighty mouse. I went in on Wed Morning and switched again. If Liz had not done a pre-switch for me it never would have been possible....but thanks to a exaggerated two-week return policy (A week and a half for the first and then another for the last) I got exactly what I want.
Yes it cost a bit more 70.00 for a mouse is a bit foolish but the flip side to my cheap-ness is that once I identify what I want
I usually cannot resist getting just that.