I've been though jabberd2, ejabberd and has since a couple of years stuck with Prosody. The main strengths are that it is very simple and lightweight, and uses

I've been though jabberd2, ejabberd and has since a couple of years stuck with Prosody. The main strengths are that it is very simple and lightweight, and uses less resources. The drawbacks is that it is simple and lightweight, so anything more complicated for corporate deployments is something you often have to roll up your sleeves and implement yourself. I was scared to run it at first because it is written in Lua, which is an unknown language to me. However, I must say it is quite an elegant language. I could get an authentication plugin running after looking at an existing one, and I trusted it enough to run in production internally for a small team (and it turned out to work well for us). Edit: Be sure to get a real certificate (startssl is fine), if you intend to use s2s. During the past year or two, most public servers has started to care.