My guess is that the "cheap" one is the newer generation one with Bluetooth (BT). Whereas the other one is the version without BT. Since it is an older model AND it is provided by Pfister, this could explain the more expensive price. I would go for the BT version. Another remark is that the specs of the BT bulb are not 100% correct, since from the official site, the lifetime should be 25'000 hours. The Wattage of the bulb is in fact 9W. But the BT/Wireless circuit needs also power, this could explain the 9.5W consumption listed here.