In all objectivity, it's probably the soundest decision at this point. It makes little sense to start allowing marriages before the final decision has been issued.
This. It is consistent and logical. Plus, in the end, I think it's pretty clear that banning gay marriage is unconstitutional. SCOTUS will make the appropriate ruling, 5-4, as you'd expect.
It conceivably could even be 6-3. If Roberts can come up with a reason convincing enough to himself to let him vote in favor of gay marriage and keep this from being a 5-4 decision, even if he'd vote against it if that were the majority opinion, I think he will do that so as to try and depoliticie the court. That truly does seem to be his major concern, how to depoliticize the court.