I'm here probably 5+ times a week (and they're closed Mondays!).
This is maybe the first place I saw in Madison that had cold brew instead of the usual iced coffee. Now it seems it's all that is served, but there was a time that wasn't the case! Mermaid's cold brew is really really good. Food is also really good, with the best sandwich I've had in Madison - the banh meatless (no mayo!)
Wonderful owner and staff, overall a really friendly place that I'm happy to support!