I received my Withings BPM a few days ago and paired it with my Sony android phone. I am very disappointed with the device. 9 automode measurements out of 10 fails. I have carefully wrapped it on my arm according to the instructions in the manual. The air pump does not lift start pressure high enough, most often only up to 160-170mmHG, which is not enough to measure my often high blood pressure. The electric motor with 4 small AAA batteries seems too weak and under-dimensioned, not giving pressure enough and stops pumping too early. This causes the measurements to fail. I have tried with 3 different brands of alkaline batteries, all fresh batteries. Did not help.
My old device, an Omron M7 with a similar type of cuff works without problems. It always lift start pressure above 210 mmHg. It has a far much more effective pump powered by 4 AA batteries. The Withings device is a useless toy compared to my old Omron.
The wireless connection is nice, but wireless connection does not compensate when the meter itself fails.
I also have a Withings WS-50 scale which is a great device, the scale is accurate and Wifi a most nice feature, but their BPM is useless.