Well, I own a Lenovo Android tablet, a Huawei phone and now an OnePlus One.
Both Lenovo and Huawei stopped updating their devices after a year or so. Both have issues (rare random reboots, battery drain when WiFi is turned off). And custom ROMs are basically non-existant due to the hardware used being practically unsupported (HiSense CPU on the Huawei phone, Nvidia Tegra chipset on the Lenovvo tablet).
My OPO has none of the issues reported by some, it uses the basically the same hardware as other high-end Android phones, it comes with CM installed -- chances a way better that will be able to update it 2 years down the road.