Even with PackageControl, installing and updating packages on each of your machines is more work than it needs to be.
Instead of doing that, just move the Packages directory to your Dropbox or Google Drive and symlink it so Sublime Text can use it.
The formula:
mv SRC DEST
ln -s DEST SRC
On your first system:
mv ~/Library/Application\ Support/Sublime\ Text/Packages \
~/Dropbox/appsync/Sublime\ Text/Packages
ln -s ~/Dropbox/appsync/Sublime\ Text/Packages \
~/Library/Application\ Support/Sublime\ Text/Packages
On subsequent systems:\
rm ~/Library/Application\ Support/Sublime\ Text/Packages
ln -s ~/Dropbox/appsync/Sublime\ Text\Packages \
~/Library/Application\ Support/Sublime\ Text/Packages
The really great thing about this is that Sublime stores your preferences in a package called User so all of your preferences come along for the syncing ride.