For what it's worth, Reaper is the most appealing choice to me so far.
While I'd rather not have to spend so much time getting it to look and function the way that I prefer, at least it can be done. Some of my other prerequisites were an integrated notation editor, support for instrument definitions, and full support for my Alphatrack control surface. Reaper has those things, and as others have said, it is very powerful if you take the time to learn it and customize it.
It's also not owned by a large conglomerate that doesn't really understand DAWs. It's owned by a person who is passionate about DAWs and is directly involved in Reaper's development. There is also a pretty good user community, from what I have seen, though I haven't had any personal interaction with that yet.