We have been on 15 cruises, but never on one of the huge ships. We are active, late 50s/early 60s, and use ships as a way to get to multiple places with only unpacking once - the ship is not our "destination".
The ship was nice enough, but we found the layout didn't work well, at least for us. We enjoy sitting in a lounge looking out the windows, and there is no place on this ship to do that. You can sit outside in Spice, and we did that on sea days, but having no place to sit and read, have a drink, and watch the ocean is a deal breaker for us. We also didn't like the setup of the atrium, casino, and O'Sheehan's. While eating in O'Sheehan's, it was impossible to have a conversation due to the music or show or whatever that was going on in the atrium. We also had the worst service on any ship ever 2 different times in O'Sheehans (after not seeing our waitress for 15 minutes, asked another wait staff for a glass of wine, and being told it wasn't his table - twice).
We had an inside cabin, and it was fine - nothing special, but you don't expect special in an inside cabin!
We booked a guarantee cabin, and got what we paid for - albeit the lowest level of inside, but I don't think there is much difference besides the deck number. The cabin was just fine, not a lot of extra space, but we expected that. We had plenty of storage, and didn't mind the split bathroom setup. The power outlets being under the desk wasn't very convenient, but we had read about it, and took a short extension cord to bring the outlet up to the surface of the desk.
We enjoyed Barcelona, and spent a week before the cruise seeing the city.
We set up a small group tour and saw most of the highlights. Enjoyed walking through the Kasbah and seeing the coast
We talked with taxi drivers and chose one. Great trip up to Teide seeing the different ecosystems on the island. We recommend going to Teide
We walked around town, and went to one of the Madeira wine lodges and took a tour/tasting. We enjoyed that very much. We then took the cable-car up to the top of the hill, and watched the folks in the sleds, but the line was too long for us to want to wait. Nice town to walk around.