Viber VS NimBuzz , which one to choose for Free calls ?

               There are many Free calling  Apps and the mobile VoIP sphere is constantly expanding , none can resist the use of a free calling app to call his friends and family ,  so this service attracted several millions of users .

              Viber and NimBuzz are one of the most used free calling apps . In order to compare them i have to give you the most important details for me as a user  :

Viber  

• Free Voip calls , free instant sms and location-sharing  with Viber users  
• no registration , password or invitation required 
• automatic detection for your contacts who already use Viber 
• available on IOS , ANDROID , WINDOWS PHONE , BLACKBERRY , NOKIA and BADA .

NimBuzz

• Free Voip calls , free instant sms
• you need registration and invitation required 
• automatic detection for your contacts who already use Nimbuzz to send them an invitation
• available on PC , IOS , ANDROID , WINDOWS PHONE , BLACKBERRY , NOKIA and JAVA 

After using Viber and NimBuzz i have realized these points :

• both insure free calls and sms 
• registration required for Nimbuzz and for Viber not 
• Viber interface is like your phone contact list . otherwise , Nimbuzz interface is like IM software 
• Nimbuzz support java and pc so it can be used for a large number of users 

•  it does not support ads plus it constantly runs in the background without draining the battery of your phone.

Finally , it's for you to choose which app is adapted for you .