Which is the best Mobile VoIP SDK?

Aim of this exercise is to get a useful information for all of the SDK´s exposed below due to I am looking for VoIP SDK to develop an Application for Android / IOS. The APP requires some VoIP functionalities quite simple:

  • Make / receive SIP calls
  • Mute Speaker.
  • Mute microphone.
  • Audio conference.
  • Multi line support
  • Multi SIP accounts.
  • Caller ID.
  • DND (do not disturb).
  • IM (instant messaging).
  • AES (acoustic echo suppression)
  • DTMF (Dual-tone multi-frequency)
  • PLC (packet lost concealment)
  • AGC (automatic gain controller)
  • Noise suppression.
  • Voice activity detection
  • Support SRTP/TLS
  • Adaptive Jitter Compensation.

As I am not a programmer, the idea is to hire a professional and provide him the SDK, plus the APP full description, mock-up´s…

After previous work done, the best options we found are (not limited):

  • MEDIA 5-FONE (waiting for quotation)
  • ABTO
  • PORTSIP
  • CONAITO
  • ANTISIP
  • ZOIPER (too expensive)
  • JUPHOON (too expensive)
  • VAXVOIP (too expensive)

Of course, budget is limited and one important criteria (initial cost, maintenance, yearly/monthly royalties…) but I am asking for your experiences, comments, knowledge, etc. regarding to the next main subjects:

  • Sound Quality
  • Low memory and CPU usage
  • Bugs and programming issues. Previous know-how required
  • Support