I think miss nessa has both. I think the difference is that the pack and play is softer because it has a thicker layer of the soft silicone over a thinner firm core. You should check out her reviews and send her a message if you still have questions. She is very sweet.
Technically, I don't have either yet. I received my Mark, but it was damaged, so I had to have it replaced. I'm currently waiting for the replacement. I also plan on eventually getting the Pack 'n' Play No. 2.