I have been using it already for 1.5 months - it never lags, never hang, never freeze , no auto shutdown, no auto reboot. I am not exaggerating - is a fact. I must say this is close to the perfect phone I have ever use. Tweaking it further with different roms, using Tegrak voltage controls - battery life has improved. I'd say it is getting better every day
Some users faced issues because I think they have been installing a lot of unnecessary stuffs . I always believe don't flood your phone with junk apps you never want to use. In any category of apps - choose one or two that serves you well, example battery life indicator : i know some guys install 4-5 types - what is the purpose ?? One is good enough if it shows you the temperature and voltage. Users will face lag too if they resort to install apps from blackmarket which is notorious being Trojan carriers - it is common knowledge some of the apps from blackmarket causes auto reboot, hanging issues
Some golden rules I always practiced :
1. Factory reset phone the first time you get it before installing any 3rd party apps
2. Regularly ( I do it once a week) - go to recovery mode and
clear cache partition and dalvik cache - this si analogous to cleaning up your house. Data will still remain intact
3. At least once a week, use the phone from fully charge till empty and charge it back full
until now i never really understood what it does. Is it something like defragmenting our hard disk?