In terms of interview is more or less the same, you will be asked to solve general business cases. To prepare for those interviews is important to read something about the digital practice and the market in general, because you will be asked to motivate your choice.
The only thing that you should be really considering is that you are gonna be part of the digital practice, sobe sure that you like that field. Talking about the exit options, they are exactly the same. You will be part of teams composed by both generalist and "digital" consultants.
If your aim is to enter BCG and you like the digital area I would strongly recommend to keep going with the application for Digital BCG.
Feel free to contact me if you want more information. I myself have done with success the interviews for digital McKinsey.