IMO it's not worth the $$$. The medical data that you really need to be able to convey when you're nonresponsive are:

name
serious allergies
MAJOR medical problems
a contact name/number

This is easily handled by a custom dog tag, engraved bracelet, and/or laminated wallet card. All of which are cheap, waterproof, non-computer dependent and easily accessed by EMS and hospital personnel.

Unless you have some type of extremely rare and dangerous medical condition, I don't see the need to have all your medical records immediately available to God knows who.