Shagga
The MS Bluetooth, is probably a good mouse, but for gaming, the MX700 far out performs it.
I found the MS Bluetooth to be sligtly laggy, where as the MX700 aint, so i got the MX700.
You have to replace the batteries in the MS bluetooth everynow and then, where as the MX700, you dont, just place it on the charging unit. So the MX700 is cheaper in the long run.
Having to buy a expensive mouse mat, just to get decent performance out of it, also adds to the already large cost of buying/sustaining the mouse.
When you buy the MS Bluetooth mouse, all you are buying is a Bluetooth reciever/transmitter, and a normal MS cordless, coverted to use bluetooth.
I use my Mobile phone next to my MX700, and the mouse still works fine, it affects my wireless headphones though.
On a side note to MX700 owners, and to philip if he buys the MX700.
Logitech reccommend a white piece of paper as a mouse mat, to prolong the battery life even further, and slightly increase the accuracy.