I agree, Celebrity is much higher on all their add-ons. On Princess you can get a bottle of Jim Beam bourbon delivered to your stateroom for about $18.00 for 375 ml, or $36 for 750 ml. On Celebrity the same bottle(s) would cost more than $100. Their specialty restaurants seem to be priced with the idea that they are serving you a $40 meal in the MDR, so for $29 or $39 extra they will serve you an $70-80 meal.
I upgraded to the Premium drink package and found the upgrade price reasonable, $9.50 per day. The wifi upgrade was substantially more expensive, and I've resisted the impulse to upgrade. I like to be connected, but $13 per day extra on top of what I've already paid just seems pricey.