Some good smartphones with their bugs or customers complaints. Please these are based on customer's reviews and complaints.
(1)xiaomi redmi note 2 ; a great phone, but battery draining very fast, camera not as good as lenovo k3 note.
(2) lenovo k3 note ; great phone, but has heating problem and screen not responding at sometimes.
3) gionee m5; great phone, but battery draining very fast. Not as expected.
4) ulefone be touch 2; great phone, but battery draining very fast, poor wifi signal, no led light notification, some part of screen become dimmer sometimes.

Don't tell me you have used all these phones

Ifone 6plus: great phone.. but the screen becomes Sooo hot, when playing ordinary candy crush.. ..

Bbz30: great phone, nice keyboard.. but shortage of apps.. was able to load play store in it... it still pains me that ordinary snap chat no gree work for bb. Using such apps in an ifone, ur data go hear am

Seems there can never be a perfect phone

Meizu m2 note ; great phone, but Google services not working, difficult in downloading, is like you are not using android phone. Almost a single Sim phone. Backside is nice, but a bit too slippery - even slips over anti-slip mats!
- Meizu Security Center is a good idea, but buggy at the moment - it kills tasks in the background even if asked not to. Most annoyingly, it stops music playback. Had to root the phone and uninstall the security center to make it usable. Then a few days later, that Security Center reinstalled itself and started messing things up again. I'd expect Meizu to fix this rather sooner than later. This issue is present in Flyme 4.5.4A.