I've no idea, I use neither.
I appreciate but don't need advanced midi features like Cubase's Chord Tracks or whatever they are called. What I do need is basic reliability and stability, the ability to loop record (in "take" mode), a serviceable piano roll and event editor, straightforward workflow, works well with Kontakt, and can handle midi-transmittting VSTis (like Cthulu, or Kontakt in its "send midi to the outside world mode", etc. ) which drive other VSTis.
In these respects, how if at all is Reaper lacking? I'd really love to hear -- not from fanbois -- but from people who have actually used recent versions of both Reaper and Cubase.
*Please* don't let this descend into a tribal slanging match. Not in the mood.
I never thought I'd be serioulsy considering Reaper. (I tried it a few years ago, everything just felt so foreign and opaque; wasn't helped much by the "Oh, just spend two weeks custiomizing it and then you'll be good to go for your first project" crowd; these people are like Mormon missionaries, nice enough, but unwilling to change the subject