If it's based on existing 3rd party libraries then I imagine there are some things that don't work, on the other hand it might do something a bit more exotic like sandbox adobe apps.
Parsing the PSD format is quite a challenge given its "half-open" nature. We've looked at many different libraries out there and basically took the best from each. Now we're also contributing to the open PSD.rb implementation.
If it's based on existing 3rd party libraries then I imagine there are some things that don't work, on the other hand it might do something a bit more exotic like sandbox adobe apps.