Our documentation team of two uses Flare and we love it for all of our documentation needs. It took a few years but now most of our doc has moved over from Word and other sources to Flare.
One product that can't move from Word is one that one particular SME authors himself. He is an excellent writer and formatter. We hardly need to touch his edits. We proof them for typos but that's about it. He uses the documentation as his spec sheet. So he documents first and then codes the software. It's the way he has worked for nearly 30 years.
Several years ago we needed to start creating Eclipse and stand-alone HTML help for customers. Since Word can't really output these types, we sought a product that could be used to do the conversion only. We needed to maintain the documents in Word. To this end, we found Doc-to-Help (Flare did not output Eclipse at the time). It was a bit of a struggle getting things to work properly. There were a number of issues that needed to be worked out and I still have four outstanding bug reports that have never been addressed. I have work-arounds to deal with these issues.
When Flare added Eclipse output, I wanted to look into using it for this purpose instead of Doc-to-Help because the product is far superior in many ways and the technical support is the best. Now that MadCap owns Doc-to-Help it's getting better, but they still never seem to fix my bugs. But I had already spent a great deal of time setting things up for the Doc-to-Help and I didn't really want to have to do it all over again for Flare.
Finally, a few years later, I have reworked our scripts and workflow to do the conversion in Flare. I'm very happy with the outcome. If anybody is interested, I would be happy to share some information about our process.