PhonerLite named the best free SIP client in the well known russian social IT-related portal HabraHabr.

https://habrahabr.ru/company/onlinepbx/blog/165799/

Enjoy!

Well, in short author states PhonerLite is popular, but some features are not obvious for beginners, e.g. tfransfers and choosing in/out devices. Then http CRM integration and record mentioned. At last long list of advantages including very good stability, which is best even comparing to many commercial softphones in the authors opinion (btw, author is the founder of http://OnlinePBX.ru - russian virtual PBX SaaS, based on FreeSWITCH).
Also three disadvatages listed: no limit for simultneous incoming calls, closed sources and icons artwork (thou it is 2013 date).

and you welcome translate entire article with http://translate.yandex.ru for example

I've tried serveral sip clients And Phoner is just the best.