Ardour is free, too, and a bit more like Reaper, as it sounds.
I don't know ocenaudio; I had some people do tests with it. From the screenshots, it looks like a fancier Audacity with maybe (I am not sure) less functions Way sufficient for LibriVox, I'd say and a good programm to begin with, I suspect. No DAW, as Reaper or Ardour.
Best to avoid it in the first hand Ardour for example doesn't have a noise removing tool (or I didn't find it yet). You need to work with equalizer which is kind of challenging .