WhatsApp Voice call Review - Not Best, but Good

hi guys,
yesterday evening around some 7 pm i think, there is a buzz in desidime that whatsapp activated their voice call servers, so who already have feature activated will call other, so other guy get activated, indeed the both users have to use latest version (not same version)

i installed in next second as i am curious about whatsapp voice call,

Play stor have old version so guys told me to install from official site
http://www.whatsapp.com/an…d/

Version 2.11.552 (now Version 2.11.556 is the current – voice call activated guys are not recommened to update)
i installed and PM’ed one DImer, in next second i got a call from him, i expressed my thanks.

when i check the dashboard, it changed and small call symbol is placed next to Pin button, i tried to call my friends, but all things showed that contact doesn’t have latest version, tell him to updatate.

I called directly (normal voice call) and told my friend to update and ping me, he also updated in 10 seconds, i called him .OMG, i got it, my first call to my friend works like a charm,

he was in chennai (vodafone)
My network is Railwire Fibre wired (wifi)

Quality is not good and echo’ed once (as few old guys expressed during first launch they got 3 echo, now atleast only one)

My second call to guy in same network => call quality is awesome and clear (No echo)

My third call to guy in London, that call quality is even better than normal voice calls (No echo and hiquality clear voice)

So i think, Quality of voice call depends on nework.

Airtel => good
Vodafone => getting echo
Bsnl => no echo, but not clear like airtel, better than vodafone

Offtopic:
After voice call activation, i not used normal voice call, mybalance is same, thanks to whatsapp, hope they improve the quality.