I have been a proud owner of Lenovo K900 for almost a month already. Sold my Galaxy Note II and bought this never regretted it.
So far have been very satisfied. Battery life is superb, as the performance.

1. i didnt like the stock launcher. Especially the clover lockscreen. Resorted to Go Launcher, works perfectly without any lags. ActiveNotifications as replacement for clover lockscreen.

2. Loudspeaker during calls is particularly unsatisfactory. However i didnt update the firmware yet, expecting this problem will be solved after that.

3. Am using the transparent silicon case n screen protector - its all i need!