Hi Rob,
Jumping onto an old post, as this is something I was also considering. When I installed last week I was inclined to go with the latest stable version. But The work "experimental" threw me off track, so I decided to go with 11.
To make sure I'm understanding correctly - you're saying that the command you referenced ("asterisk-version-switch") will put me up to v.13 with no risk to the current configuration? Only reason I'm thinking about making the switch is the inclusion of pjsip. Not sure if that's really a compelling reason. But some of the tutorials I've been following use pjsip instead of sip in several scenarios.
Thanks!
Brian