Even though internally Baby SliceO does look a lot like sliceOmatic, internally, it is a completely different beast. Baby SliceO work and think in 3D. It is design to work with 3D datasets.
Here's an list of the main differences.
The Modes
All the modes present in sliceOmatic 5.0 have been replaced by new modes. these new modes are designed to help in the creation of 3D models. They work with the GPU using massively parallel algorithm to interact in real time with the datasets.
The Classes
Even though a few classes are still present in Baby SliceO, no tools are provided to the user to manipulate them.
Multi Windows and Multi Modes
You can have up to 4 active windows (like in 5.0) but these windows have pre-assigned modes. Window 0 will always be 3D, and the 3 other 2D windows are design to each display a specific orientation of the dataset. Also, all the windows are in the same mode at the same time (if you are in edit mode, all windows are in Edit).
The Surface/Volume Tool
The Surface/Volume tool is not present in Baby SliceO. This program is not designed to make measurements but to create 3D models.