i. You better be using exactly the same org-mode version on all of your computers, because there is no concept of backward compatibility. Making matters worse, there is no restriction that changes have to be documented before the release. I got burned with some presentations when they made major changes to the exporters. The documentation consisted of a statement that they were working on the documentation.
ii. The documentation you find may or may not work. Google is hit or miss because in most cases your search will return an answer for a different version from the one you're using.
This is not to say you shouldn't use org-mode. As I stated at the top of my comment, I use it on a daily basis, so there are a lot of benefits. Nonetheless, org-mode discussions paint a rosy picture, when there are in reality issues that you have to be prepared for.