Having been on a couple cruises before this (with Royal Caribbean) I looked forward to seeing the differences between the two lines. Both times on Royal Caribbean we had sailed on the Sovereign, an older boat but still lots of fun.
Fast forward to this cruise, we set sail on the Inspiration which is a slightly newer boat than Sovereign. Getting onto the boat was quick and easy. We even had to split billing between rooms and that was a breeze during the check in process.
Getting on the boat we always get the fountain cards for unlimited soda. While the price was reasonable Carnival doesn't give you a soda cup like RC does and you also have a separate card instead of a sticker. If you want a soda cup they will sell you one for $4.95 (w/card) or $6.95 (w/o card).