I'll second the double-sided, and note that since you want to use it on the street you should get one that can take a lockring on both sides. Some are made for a freewheel on one side and fixed on the other, and only can take a lockring on one side.
the other thing to keep in mind when you're starting is equipment compatibility-- the miche mounts cogs more like on a freehub and is incompatible with what most people use, so if you're on a budget and sometimes find you need to borrow different sized cogs from people then the formula is better. It would also mean that you'd have to get all miche hubs as you expand your collection, or buy new cogs when you start to accumulate some threaded hubs.