Peter Kirn has a write-up about a new release of Ardour:
http://createdigitalmusic.com/2015/04/reasons-new-free-ardour-4-daw-good-news/
I can’t see myself dropping Renoise as my primary composition tool, but I currently use Reaper and (to a much lesser extent) pixitracker as supplements to my Renoise hacking.
The big news here might be improved support for OSX and Windows.
(OTOH I did actually buy Mixbus a few months ago but have not quite gotten around to doing much with it.)