A functional and easy-to-use tool that would be great for adding/editing elements in modules, if not for 2 major bugs:
Rarely adding a copy of an object, undoing a delete, or sometimes even just double-clicking on it can mess up X,Y-orientation of half the objects in the module and break/remove/move half the triggers. It's easy to miss when this happens to objects on the other side of the map. Usually you can return everything by clicking the 'Undo' button, but if you saved and closed the module, it is faster to repeat the work from scratch.
One time after saving an edited module in KotOR Toolset, it became corrupted: the module would not load in the game and would not open in the tool. Therefore, always have a backup copy of the module you are editing.
Because of these issues, I had to use KotOR Toolset to only view the objects, their coordinates and positions, and do all the actual editing in K-GFF. Still, KotOR Toolset greatly simplifies and speeds up the mod development process. It's a pity that this great tool can't be used to its full potential.