Sweetmarias has a grinder comparison chart that might be helpful as it goes over some highlights and key details.

In general I think the way to determine what grinder to chose is based 1) on how you drink your coffee, 2) how much coffee you drink and 3) how much you want to spend (which tends to related directly to how long you want the machine to last).

If you are drinking mostly drip coffee, you might want to just use a simple whirly blade mill which is not expensive, they tend to last fairly long, and they do an okay job. If you don't grind much coffee, then a hand mill might be a nice alternative to the noisier whirly blade mills.

If you grind for espresso - more than say a cup a day and want a mill that will really last, then it is worth it to spend more for a mill like a Rocky or a Mazzer - something that has parts that can be serviced or repaired. 

The mid-priced burr mills like the Maestro Plus and Virtuoso are designed to do a range of grinds and  last fairly long - several years at least.