After you flash to Dev ROM, make sure you get "Google installer" from Mi Market.
Install all the relevant apps via "Google installer"

Once the relevant apps are installed, make sure you reboot your phone!

Then everything should be okay now.

and you can start enjoy few feature which Stable ROM doesn't have it.
p/s: some application will crash but just reopen will do.

edit: go to your Updater > press "Menu" button > choose "Get latest version of MIUI" > at the bottom have "Update"
if beside the "Update" have some 450~500MB, mean you required to download and install the package once more.
I just remember this, because I been into your situation for few hour and go through these step, everything is settle.

Update here after that. 
If really stabil and not really alot buggy , i will consider up to dev rom again. 

After you flash to Dev ROM, make sure you get "Google installer" from Mi Market.
Install all the relevant apps via "Google installer"

Once the relevant apps are installed, make sure you reboot your phone!

they do provide adapter for micro sim..

ehm... whatapps does not seems to be verifying my number thru the SMS... >.<'

Time to get ready for V6...i'm adding new post topic on "Modding Mi3". Stay tuned guys!
What's the error message. need more details to assist you bro.

Something u guys should know

http://en.miui.com/thread-22524-1-1.html

i use swype : https://play.google.com/store/apps/details?...uance.swype.dtc

swiftkey got chinese keyboard too.. just download