I have no idea what happened to the first post. It originally contained an introductory text, but the forum (or a person) cut off everything after the first line due to a bug or accident or whatever months after it was posted. IIRC, sometimes when I've looked at this thread, the post was back in its entirety just as mysteriously as it vanished. It's notable that that post also doesn't have an "edited by" label. It confuses me a great deal.
Yes, Microbrush is a 3D modeler that also handles VMF files. Its purpose is to speed up the rough brushwork which takes ages to do in Hammer. At the moment, I am working on a bit of texture support so that texture information is retained and can be edited.
The bottom of the project page lists some other editor projects worth checking out, too.
Project page: http://shrinker.seriouszone.com/projects/IterationX/Microbrush3/
Twitter: http://twitter.com/Shrinker42