"New" PJSIP feature any info?

Just installed latest Freepbx12/Asterisk13 distro
I’m totally unaware of new PJSIP feature, but playing around I have it working both in extensions and trunks
Anyway I come to ask you what are the real benefit of PJSIP vs chan_SIP , when and why should I use one rather the other , or when I shouldn’t use one of them
I haven’t found any “common mortal” explanation of PJSIP pros and cons on the web
Could anybody clarify a little, please ?

Thank you


Thank you for quick reply
Very useful link

Very good article thank you