We have been on one Celebrity and one Princess so its not as much experience as most people on these forums.
Celebrity Equinox 2017 (Aqua)
Princess Discovery 2022 (Balcony)
Ships are very similar, staff all great, service great, entertainement similar, food choices similar, fitness choices the same. Most of the time you would most likely not notice if you were on a Princess or Celebrity cruise. In our opinion
Celebrity
Pro
Food quality slight edge
Wine quality by far
Embarkation/Debarkation very smooth
Aqua Class (Blue resturant)
Con
Internet
No self laundry
Covered Adult pool (which allows kids sometimes)
Princess
Pros
Self service Laundry
Free food seems so much better like pizza for example
Adult pool is outside and no kids allowed
Cons
Embarkation/Debarkation not great
Wine at the bars
Internet