Totally agree with our 1st point, some premium functions are extra but when come to real life it is not a must(or waste if you din even use the function after you purchase the devices).
-For dual sim phone, MTK processor is most common and cheaper choice. MTK6589T is the latest powerful processor of MediaTek, if you could wait till next year, they are coming with REAL octa core processor.

-Battery part, if you want your phone to last for one day with 3G data on all the time, Phone that come with 3000mAh battery and only 720P resolution will be your choice, when go to FHD screen, you need to control the 3G data on time or an extra battery.
-When talk about gaming, PowerVR SGX544 with clockspeed 544MHz that come with MTK6589T processor is good enough for casual gaming, but Minion rush is somehow a exception, before the latest update, it run really smooth on my ZOPO C2(flagship), smoother than Nexus 7, but after the latest update, it was crap, I do believe is the apps compatiblility, other game like AVP, Real racing 3, Dungeon hunter 4 are running smooth.
-1GB or 2GB ram? depend on what you need, if multi-tasking alot, just pay alil more for 2GB and normall come with 32GB ROM which will worth the money.
JIAYU G4 come with large battery capacity, it have really good standby time.
THL I have no comment, never have chance to touch this brand.
ZOPO C2, it have really good display, 5" 441PPI FHD display is really good, the front camera is 8MP instead of 5MP. But it have weaker performance when come to battery, it can last for one day if connect wifi most of the time with some moderate usage. IF you turn on 3G most of the time, you really need an extra battery.
Hope this will help you.

Thanks dude. Really help to reconfirm some of my thoughts.
I'm quite interested with JIAYU g4...it have 2 version is it, youth and premium version? Is premium version available locally? Can anyone tell me the seller and price?
The premium version is still not available locally as far as i know. But the price should be 950-1099.
Heard that most online sellers keep bringing the price for premium version higher and higher due to demand.
Check the price when it came out and decide again. I personally wouldnt want to spend more than i should for something that has a high price due to the high demand instead of value.