Microsoft mouse for iMac

Since I made the switch to Apple computers (about 3 years ago) I could never get comfortable with Apples mice. When the mighty mouse came out I finally thought they had a mouse that would be superior... and well after 3 months of owning one, the scroll ball stopped responding to me, so without hesitation I went right back to my old Microsoft wireless optical blue mouse. Well finally Ol' blue has been crapping out and it's time to buy a new mouse. As far as apple products go they still carry the same mighty mouse that crapped out on me after 3 months of use... so that brings me back to Microsoft products... I've mostly been looking into the bluetooth products (as to not use up a USB port) however I can't decide which is better. I've looked into the Microsoft Bluetooth 5000 and 8000 and it would seem that only the notebook version of the 5000 comes with bluetooth and the 8000 gets bluetooth in both the "desktop" and notebook version.

Notebook versions of mice seem like they could get uncomfortable after a while, anyone experience this?

Anyone know if there is a "desktop" version of the 5000 that utilizes bluetooth?

The 8000 desktop version mouse unfortunately, is not carried by any stores nearby for me to check out. Has anyone used the 8000 desktop mouse? Any good?

I haven't used either of those mice, but I have a suggestion for the Apple Mighty Mouse. Perhaps you've tried this already, but the scroll ball sometimes just needs to be cleaned to work correctly. You can clean it with a soft cloth (I use one that I got for my display) by rubbing hard back and forth on the ball. That usually cleans out the gunk that gets stuck in it.

Sorry I can't help with the MS mice. Most of their mice are too big for my small hands so I use the Mighty Mouse or Logitech mice.

Claire