Just use SlingShot to publish your stuff from one Mac, and then use SlingShot on your other Mac to subscribe. Tell SlingShot how often to check for updates, and you're all set...SlingShot will silently work in the background keeping all your bits in line.
SlingShot will copy over any songs from the playlist that aren't in the Subcriber's iTunes Library, add them to its Library, and then recreate the Playlist on the Subscriber. Then it will check periodically (you tell it how often) — add a new song to the Playlist on the Publisher, and the Subscriber will do the same.
Want to send only some songs over to your laptop before a trip? Make a playlist on your main computer and Subscribe to it on your laptop. SlingShot will grab all the songs on the playlist, add them to the iTunes Library on the laptop, and recreate the playlist.
Want to automatically have the music you've purchased from the iTunes Music Store copied to all your Macs? Use SlingShot to Publish the Purchased playlist on one machine and have your other machine Subscribe.
SlingShot is still the best way to keep folders full of regular data files synchronized between your macs, too. Just use SlingShot to publish your important folders and subscribe to them from the other machines. SlingShot will make sure to keep all your files up to date, checking as often as you want for new updates.
When you're publishing a folder, SlingShot also allows the publisher to choose to accept updates from subscribers. This makes it really easy to keep your data up to date on all your Macs, no matter where you happen to edit it.
