I have only been on Princess so I can't give you a comparison;
but I can tell you the mini-suites are great. 323 sq.ft. (incl. Bal.), large sitting area with sofa bed. Two T.V.s, fridge, large closet, and best of all, a large bathroom with tub--no more getting out of the shower if you drop the soap! And the balconies are huge; we had two small tables, two chairs and two recliners.
I would recommend a Princess mini-suite without any hesitation.