I doubt the differences between the official Win8 plugin by scirra and your metro plugin, i noticed the official doesn't come Live Tiles
The official plugin is still lacking features. The plugin that I am working on currently has a lot more to offer: provide options in settings charm, Live Tiles(as you noted), Local Data, now In App Purchases with r6 and more in pipeline.
Please refer the manual for the complete list of features!
If you would like to have more features, let me know! :)