I love the way Lightning components are handled in TWL but the at the moment you cannot add all the files needed (SVC, Design Etc.) to the Lightning pacakge meaning you still need to use another tool to create these.. Also, when creating a new Component you are not asked what it will be used for (App, Record Page, Community Etc), although these can be entered manually in the cmp file, it would be far easier if this worked as per the Developer console in SF and gave you the option to select. There is also no option to specify "Lightning out" when creating.
When rendering the Component in an App in the preview window, the fomatting does not look right and seems to ignore any Styles and Icons.
If these few issues can be fixed then TWS will be an awesome Lightning development tool