Currently operate CS4 and am interested in upgrade to cloud CS6.
If I opt for download as opposed to shipped package, what happens if my PC ever crashes or need to re-format, etc. How would I be able to re-load the Adobe software?
As long as you are using the same computer after a crash or a re-format, you can reinstall the applications from the Creative Cloud membership website. You can have your Creative Cloud memberhsip activated on two computers.
Here's a previous question you might find helpful, regarding activation on multiple computers in the case of a crash: http://forums.adobe.com/message/4452899