Our favourite text expansion app for Mac, aText, has just been updated. You can now enable sync your snippets so you can use them across computers.
Despite the price, Text Expander always had a leg up on aText because of its syncing features. Now that aText can sync via several services (e.g. Dropbox, Google Drive), it's on par feature-for-feature with Text Expander, and it costs a fraction of the price.