It depends what you mean by integrate
we use comatose, which is not as fully featured out of the box as some of the cms systems you mentioned -
but allows extremely tight integration of your rails webapp with the cms.
Really, as with all things, it depends on your needs -
if the content parts of your site are very separate, then no problem:
use one of the cms systems in your list that you like, perhaps radiant just to keep everything rails-esque.
if commonly a single page will include embedded content you want to manage, and at the same time display a view from your rails app,
then you either need to go with something like comatose which plugins into your rails ap, and let’s you embed content with render calls,
Anyway - that was the thought process that lead me to comatose - of course I have no idea where your needs lie, but there’s my 2 cents anyway.