The Mac Mini Vault has already grabbed a new Mac mini and taken it apart. You can read through the site's teardown and analysis right now. The short version is that much of the mini's design is the same. As you can see above, with the new version on the left and the 2011 version on the right. But because of the upgraded processor and memory, the new version is much faster than the last one, with nearly an extra thousand score on Geekbench tests.
Mac Mini Vault (one of a few businesses offering Mac mini co-location) has a few more tests coming later on this week, including benchmarking on a few different operating systems running on the new mini, as well as a look at the new Mac mini server model that Apple has added to the lineup. It's great to see the mini getting some love, as it's an affordable and powerful way to run Apple's excellent hardware and OS in all kinds of different ways.