Well, I really hope the "experimental" quote has now been settled down. I myself use it for multiple quoting from all over the page (if needed) - before getting to the "Quick reply" area.
But you know what? For the LAST hit to the answer I use (have by right about now) the other one -- which was initially called "Quote (selected)". It worked either way - either without any selection -- getting that paticular entire post quoted --- or - when a piece is selected -- quoting that piece. And they both have been a pair of good partners in easy quoting for users.
Now what?

In its previous/initial state, it worked just like that in MyOpera blog comments - either way depending on whether you selected some text or not:)