I have not treated my established hives with sucrocide yet, however, when I installed my packages I sprayed them down with sucrocide and haven't had a noticeable mite problem yet. Last winter my mom noticed a bad mite infestation in her hive. She treated with Api-Stan and it cleared things right up. But than again we have milder winters so we could do that in Feb before the spring flow.
I'm planning on doing the powdered sugar method (mentioned by amymcg) before winter to get my hives ready, I'm hoping not to use any chemicals, but don't we all! :-\ Still, Sucrocide is an "organic" miteacide and that's why I'll use it if I get a really bad infestation. If I were you I'd get some, it may be more labor intensive on you and your bees, but if you have a strong hive, they'll do well.