[Device Reviews and Information] :
Hey guys ! I have successfully upgraded to 4.4 today from B609 and did not loose my apps, my contacts nor my messages (I've gone B609 -> B611 -> Kitkat release by downloading each package separately fom emui's website) so I'll give the visible differences between B609 and the kitkat release.

Not much change from a user standpoint, some nice customization features (along with "ultra battery" mode that just turns your phone from a smartphone to a 1990 cell phone in minutes :D but saves battery) but also a lot of drawbacks UI-wise (for example in B609 using the drop-down notification menu could get you to notifications or quick settings whether you swiped it from the left or right side of the screen, not anymore but the widget has been upgraded and it looks awesome. The clock + weather widget also had shortcuts to clock and weather apps, now it's only weather...).

Notification bar has PIN operator written on it, notification icons are more easily spotted and recognized

More lighthearted modifications :

Lock screen time has a lighter font and some infos (weather, quick utilities apps) are available by swiping it from the very bottom to the top. Support was added for face and voice recognition unlocking of the phone. Boot screen now has "Huawei POWERED BY ANDROID" written on it. Chinese useless crapware and unwanted google apps have been going through the roof, but you can easily remove them with a system apps uninstaller ("/system/apps mover" or rootgenius' "KingUser" allow to do that).

Lock screen SMS icon is now tiny and ****ty (I liked this smiling talk bubble face :'( ). GPS icon has been replaced. The multiple desktops on home app now loop indefinitely (meaning that the first one is located right of the last one). There is a "lock screen" app installed. The popup notifications (about root access being given or wifi network being connected to) have a different, more readable skin.

Be aware though that you might loose the phone number <--> contact association for already received smses if you live in france - there are multiple number presentations and the honor 3x does not seem to associate them very well, like +33 5 82... and +33582... and 0582...

Just adding my opinion to biobio's one

1. how is the gps lock time and is it wrking fine with navigation software w/o using internet ?

Compared to the Xiaomi Red Rice my father has it's such a breeze. I use the open-source version of Osmand and it works like a charm with the maps you can download on the internet (it takes a lot of storage though, but my 64Gb HDXC can handle it :D)

2. How is the 13MP cam quality ?. 3x has some blue-glass filter which shd take better pics.

Nice quality but well below traditional digital cameras when it comes to picture stability (lots of blur, got better recently on developer builds though) and color balance

3. any heating issues while talking or playing games ?

Not when talking. The top of the phone can get warm when you play games but I have been playing power-intensive games for a long time without issue (sometimes 3h+ on stuff like Bard's Tale and Anomaly 2 - see Humble Bundle Store if you want them)

4. how is the battery backup ?

Excellent. I see a lot of people talking about 2 days worth of battery but when using your phone mainly for sms, notepad and taking care to put it in plane mode before going to sleep you can get way more (I recently ran 5 days on battery). You can get a second battery for almost nothing with a lot of retailers though if you need (merrymobiles' one cost 5-7€ if I recall correctly).

5. how is the wifi/gsm/3g signal strength ?.

Good. No issue even on my personal raspberry pi hotspot from the other end of my house.

6. does it has GLONASS gps support ?, some specs says it support glonass

Nope.

8. does it wrk correctly with 3-button+mike handsfree. ( like the xiaomi piston earphones )

I did not try it. Maybe soon I'll ask for my father's piston earphones to try them

9. Is it possible to hv OTG support ? by adding support to the kernel ?? or hardware change is required ?

Is 3xpro already selling ?

No OTG support for now. I tried some apps and tricks to make it work but it just doesn't, you can still hope a compatible driver comes out but that's unlikely... 3xPro is already selling, we have someone in this thread who has it.