Its bit early, but my first general impressions
(a) Flyme doesn’t offer alot of things to stock android and I don’t see the point of adding such a heavy UI in a phone, especially if it keeps your brand new device in Lollipop by the end of 2016…
(b) Three or four times already in 40 days of use, phone asks me to enter pins to reconnect to my sims. Bug or hardware failure? Of course if you have your phone in pocket, you will not realise that you have lost network connection
(c ) camera is so and so, as is screen. Of course I know I have not bought a super amoled phone, still, if you go from a super amoled to M3s you will notice the difference in quality easily
(d) Quality of call could be worse than my previous phones, but this might be my impression, not sure
The good things: Good battery time, light and cheap two sim device.
Would I buy it now? No, especially due to flyme. I just hope someone would port cyanogen or ubuntu touch, though.