Which SIP stack/library is best for iOS? [on hold]

Which SIP stack/library is best for iOS? [on hold]

I am writing a VoIP/SIP dialer client for iPhone. But i am very confused
about which SIP stack should i use. I have searched all over the internet
and found about 6-7 SIP library which can be used for iOS. I have got the
following...
PJSIP(Most used. Open source C-based SIP stack. Could be good if we want
to go low-level)
idoubs (Not bad, updating continuously)
siphon (Not bad but hasn't been updated for a long time. Seems to be the
default option. Objective-c codebase with existing UI, It uses PJSIP
stack.)
miumiu (appears less mature than Siphon.) https://github.com/pzion/miumiu
linphone (Another Linux-oriented option. Rough UI but the audio engine
seems good.)
sofia-sip (Couldn't understand.)
So can someone please suggest me about which SIP library would be best for
iOS ? I will use G729 codec.