Hi there,
I reply this thread as this is the only post I found useful in the web before I decided to purchase this arc touch mouse SE one month ago. I was an arc touch mouse user (bought two) but both were laid down due to the damage to the receiver. The Bluetooth edition is really an amazing improvement for me.
I have to use Windows 7 x64 on my primary company laptop (recently replaced T440p with Intel WiFi+Bluetooth 4.0 LE 6235-N).
With the Bluetooth drivers provided by Lenovo System Update or on their website the mouse is workable but have to reconnect with the "Try again" trick every time it gets asleep. It's not a big problem and I am get use to it totally.
However after installing the latest Intel Bluetooth drivers from Intel website (17.0.1405.02, win7 x64), it is working great just as in Windows 8/8.1 as it should be!
So whether the mouse is workable is completely dependent on the support of the driver, not as claimed as Microsoft only Win8/8.1. Of course with Win8/8.1 it is more simple to set up.
I don't know why MS don't want to "officially" support this, as there are still large number of users have to be sticky to Windows 7 in the enterprise.
There is one more thing I'd like to ask MS to improve. As this mouse can only pair to "one" device. If you change the device, you have to repair it. Doesn't like BT headphone, can be paired and connected to different devices automatically.
Hope my experience could help the rest of you who is still hesitant to it.