I certainly wouldn't marry an ACTIVE alcoholic, or one without at least a year of solid recovery. My first husband was a year sober when I married him, and this January he will celebrate 37 years of continuous sobriety. My second husband was mostly sober with slips when I married him (in a burst of unwarranted optimism), and I left him a few months later in full-blown relapse from which he's never (so far as I know) returned. So I'd never recommend THAT to anyone.
As for someone with solid recovery, I'd say anyone with five or more years who seems to be emotionally stable and responsible (especially if they remain happily involved with AA) is probably as good a bet as anyone you meet--other problems, like infidelity or even late-developing addiction can come along no matter how sure you feel about the other person when you marry him/her.