Differences between Server 2012 and Windows 8 Pro?

I was wondering if anyone knew the differences between the Server 2012 edition and Windows 8 Pro (the consumer one).

I know there are slight differences between the two (generally), but I've honestly forgotten what they are...

I'm getting a free [legal] copy of Server 2012 (via Dream Spark) and was wondering if I should install it or wait for Windows 8 and pay the $40 to upgrade my Windows 7 box.