I have both. The AllData is easier to "surf" through its logical set up and you don't have to exit and restart to use sections that are on the "other" disc, like the MB. But, the MB disc contains most all you need; although, it has NO basic troubleshooting section whic the All Data does.

Personnaly, I use the AllData untill I find what I need (it's faster that way) then use the MB Disc if the AllData info is vague or incomplete.