Hi,
Yes...when you select the Information Store using the agent, it flushes your logs (unless you use AOFO and then you run the risk that you won't), and makes sure that THAT is all you need.
I have been told to back up the metabak folder in c:\windows\system32, so I do that as well.
Using the agent to back up the Exchange IS, I have successfully recovered a crashed server, so it is possible.
You can also include the server's System State if you want to restore that at any stage.
Laters!