Ulefone Power. The Android 6.0 installed on new batch of Ulefone Power is the stable version and this firmware will also be released OTA to old devices which have been upgraded from Android 5.1 to earlier version of Android 6.0. For people who have not flash the marshmallow ROM, Ulefone say they are still working on the OTA upgrade and will publish it as soon as they can.
Ulefone Power packs 6050mAh battery, MTK6753 chipset, 3GB RAM, 5.5-inch 1080P display and 13MP Sony IMX214 camera. Now you can buy it from Gearbest for USD152 or so.