The major difference is the Keyword driven approach. What was a hierarchical tree view of your business process in 6.5 has now been flattened out into a spreadsheet like view of individual keywords, with the different columns representing such things as the object name, the action to apply to the object, and the data to use while applying that action. However, beyond the presentation and some user functionality associated with it, the underlying script has not changed. There are some new features of course in 8.0, but anything you learn in 6.5 will carry over almost directly. Tool usage, methodology, best practices are all the same. FYI Training for 8.0 has not been published yet, don't know when it will be.