2
I suggest you wait till the dev team releases the 2.2.3 FINAL release. The beta testing team is working on testing that release right now, so it may not be too long before it is released. This releases fixes some of the incompaitbility issues 2.2 currently has.
Also, I suggest you create an exact copy of your websites (files and databases) somewhere (localhost perhaps?), and migrate to the new version in that testing environment. That way you won't loose anything important, and can see how the transition goes.
2.0.13.1 is stable tho, and we will keep maintaining the 2.0.x series with bugfixes and patches, so if you don't really need the new features 2.2 brings (like dynamic userprofiles, advanced block placements, extensive PM module, etc. etc.), why go there?
Herko