As a conservative I don't think it's the Federal government's business to care what consenting adult marries what other consenting adult or adults. I don't see "defining marriage" or "identifying suitable marriage partners" among the Enumerated Powers, which means it's up to the states.
I am against the SCOTUS creating legislation by the court - they need to decide that it's up to the states and get out of it.
Personally, let 'em get married - provided:
1) "Domestic partner" benefits that apply to same-sex (but not different sex) partners are eliminated.
2) Any church that elects not to perform these ceremonies is not to be harassed, sued, etc... if it doesn't fit with their beliefs.
3) It's a legal marriage - with all that implies vis-a-vis divorce and property settlement. Maybe some gender-blindness would improve some biased rules.
This is the Pub. Leave common sense at the door.