Interestingly, C1 v9 includes both keywording and masking improvements (as well as a better raw engine). I made the move to v8 a month and a half ago, and just upgraded to v9 today (with some great help from David at Phase One). I'm pretty confident that Phase is moving to better cataloging - they own Media Pro, which is a very powerful cataloging system, and the new keywording in C1 v9 (which I haven't had a chance to experiment with yet) seems suspiciously like they got it from Media Pro. My guess is that the reason we haven't seen a lot of updates to Media Pro lately is that they're busy integrating it into C1! If that IS what they're doing, when they finish, C1 will have the best cataloging system in the business.
I agree with the earlier posters who commented on C1's much better handling of X-Trans (compared to Lightroom) - that was one of the reasons I made the move (along with Adobe's import downgrade, which led me to worry about Adobe becoming more beginner-focused with Lightroom).
One huge advantage to C1 is Phase One - David reads these forums and responds regularly (and I'm sure he passes our feedback on to the development team). Their other product is $20,000+ digital backs - they're interested in the needs of serious photographers, not in converging photography and mobile phones.Whether or not they succeed with the backs long-term (and I have my doubts, both because of Pentax (and possibly Fuji in the near future) introducing MUCH cheaper MF digital, and because of the increasing image quality of smaller formats), they know serious photographers, and they're a tiny company whose whole focus is on serious photographers who actually use CAMERAS...
Much of Adobe's recent innovation is on the mobile side, and it almost has to be, given how big a company Adobe is, and the relative size of the phone and camera markets. Yes, Adobe backed down on the import downgrade, but I suspect we'll see an increasing number of beginner-focused and mobile-focused features, due to the sheer size of that market. Adobe's real long-term interest is in getting people to use Lightroom Mobile to manage and edit their iPhone photos, because so many people have iPhones.
Will Phase One ever match Lightroom's integrated modules (print, slideshow, etc.)? I don't know. I hope so - they could acquire the technology, as they seem to have done with cataloging by buying Media Pro...