Originally Posted by
SifJar Playbook is guaranteed to get BB10, and while Nexus devices generally get the next official version or two of Android, that's usually it. (e.g. Nexus One launched with FroYo, got Gingerbread, no ICS. Nexus S launched with Gingerbread, got ICS, is getting Jelly Bean but probably won't get anything beyond that. Nexus Galaxy launched with ICS, is getting JB and will probably get the next version, but quite possibly no further).
PB had OS1, OS2 and will have BB10. That's as many OS versions as any Nexus device has had thus far.