I have a Lenovo Yoga 2. The moment that I turn on bluetooth, the wifi drops out - I lose connection, and connecting again shows "connection failed". If I turn the bluetooth off, wifi can reestablish fine. I've tried lots of different combinations of drivers for both the wifi and the bluetooth, but no combination has has changed this behavior yet. I've read some speculation that the cards have insufficient shielding, but that seems like kind of a large flaw to ship with.
I've tried with a Carbon X1, a Yoga 2 Pro, and a Yoga 2 all next to each other on the desk while running InSSIDer. The X1 and the Y2P don't lose wifi connection when the bluetooth turns on, but the Y2 does immediately. The Y2P and the Y2 are running the same drivers for bluetooth and wifi, and appear to have the same wireless card internally.
During the failure state, InSSIDer still sees signal strength for my network, but I cannot connect to it.
stats:
the card that comes in the laptop is an Intel Wireless-N 7260
Intel Bluetooth driver is at 17.0.1401.422
Intel Wireless driver is at 17.0.2.5
Windows 8.1 x64
Home wifi is a Medialink MWN-WAPR150N