Being one of OpenSER co-founders and then leading Kamailio evolution after rename, I can say it was a hell of a time, with bad days in the beginning but fruitful and with happy end.
Soon after the fork, the developer that registered openser domain forked the project and redirected web site to its new toy (not to say he started (and is still) claiming that his new pet is openser -- well, check http://sourceforge.net/projects/openser/ - the OpenSER development portal hosted by SourceForge.net was created in May 2005 by myself, while the forked project hosted by same SourceForge.net is created in 2008, so no comment, you judge!).
Anyhow, so August 2008 found us in a complete mess. It was not only bad for our project, but a tough hit to Open Source telephony applications, the case being used by competition to suggest unreliability and high risk of using Open Source for major communication projects.
In such foggy time you cannot go in dirty fights, or at least is what I decided to do, I avoided answering stupid claims and statements -- would have been endless discussions, removing any kind of trust left.
Well, I did defend against some statements about members of Kamailio development team when were purely brainless attacks. As a matter of fact, the Kamailio development team was the real value.
OpenSER was at that time a good piece of software, could run for ages if you knew it to configure it properly. But the question was the future. With 5 out of 7 management people committed to continue with Kamailio, it was clear for me that it will succeed.
So, what to do in such time? How to go over a dirty fork? Calm down, focus on the future - even a kick in the back is a step forward - time will sort it out and reveal the truth.
Therefore we worked, worked worked - two years ago was a new beginning: new name (some didn't even like it then, changed opinion meanwhile), main web domain lost. What we achieved meanwhile? I would say not bad at all, see next:
- three major releases: 1.4.x (first with kamailio name), 1.5.x (an impressive list of new additions) and 3.0.x (Kamailio and SER first time together)
- next major release 3.1.x to be out in about 2 months
- received Best of Open Source Networking Software Award (BOSSIE'09) by InfoWorld magazine in 2009
- integration with SIP Express Router (SER) done by an amazing commitment from development team
- Kamailio is no longer a noname in SIP and VoIP
- large deployments rely on Kamailio
Practically these days Kamailio and SER are the same application (it is same source code, hosted by http://sip-router.org) the difference is the database structure used to store phone profiles, routing info, a.s.o. This is possible by having many extensions for same purpose (e.g., user authentication). With the time, more extensions will be merged, for sake of easy development and maintenance.
At this time, Kamailio is a far better application than OpenSER 2008 - not based on cosmetic changes and buzz words, but real re-factoring where was needed. The devel team is very solid (we had three devel-dedicated face to face meetings since 2008) with broad experience (4 out of the 5 core developers of SER in 2002 are still active in project).
We know what we developed since 2001, we will continue to develop and offer the reference SIP server implementation out there - being it your choice of SER or Kamailio at this time.