It is probably a delay in order to increase quality, but it's good that they worry about quality rather than rushing a release.
Having said that, I'm a bit sad too as I need a new installer to get past an installation bug (keeps freezes at the same package x/900 somewhere abouts). I can't update Qubes if I can't even install it.
But if you can finish the install for the RC1 version, go with that, then you can update it with the newest updates and fixes, and you should be good to go.
As for the RC2 we just have to be patient I guess, it's ready when its ready, quality trumps over rushed releases, which is a good thing as well.
Although if I had to criticize anything, it isn't any delays, it is the lack of communication. It would be nice knowing what is going on rather than being kept in the dark. But in the end of the day, we shouldn't complain if we don't pay for it.