@zepolo Thanks for pointing that out. That FAQ was written some time ago (we have been working on the new features for a long time), and is out of date with the version that we released, with which the situation is much better.
It now says:
Yes. You cannot use two page caches at the same time, and should not try. However, the WP-O page cache will only be switched on if you choose to turn it on; otherwise, it will have no effect on the site (either cacheing or performance). It is not turned on by default. Thus, WP-O can happily co-exist with other plugins.
(N.B. Also, because of how page cacheing works in WordPress, it is not possible to have more than one turned on at the same time; they might both think they’re turned on, but in effect, only the most recently turned-on will be doing anything).