Oh boy. Redmine has been forked now? There are many, many comments here, which I’ll be reading through. I’m a fan of Redmine, and I fully intend to continue using it.
There are certainly a number of alternatives out there, but the appeal of Redmine is that it is widely used, and as such, all the plugins you could ever ask for have already been created. I also like its high level of configuration and the fact that it works well for multiple projects (unlike Trac, which I loved until the day I saw Redmine).