More I use Lightroom the more I seem to find things in it to love. Adobe introduced 'Face-detection' in their last 'Lightroom CC' version but I didn't really care for it that much then. I thought it would be the same lame implementation as what iPhoto has had for years. However, playing around with it this morning I realized that it can auto-tag faces with keywords that correspond to the faces! This is huge and an incredible time-saver for me. Tagging keywords for people's names in a photo is an important but terribly arduous part of my workflow so I was really happy to see this new feature.
Wow - it took us over 15 years of digital photography and key-wording to realize that some of our keywords are actually 'persons'! And that's really key about this new feature I think. Face detection tags are really just enhanced keywords.
The tagging interface is quick and the recognition of faces seems good enough but not great quite yet. Hopefully it will only get better with time.