Just returned from the 9-night cruise on Dec 10 to the Mexican Riviera from San Diego on Carnival Spirit and, unlike another reviewer, I thought the entertainment was excellent. Seriously, this is a party ship. If you're worried about too much adult entertainment then sail Disney! Compared to a Celebrity cruise to Alaska last October, where the show music was canned and the performers suitably uninspired, the Spirit shows were creative, colorful, interesting, well-sung, well-danced, and the 8-piece band lead by a young lady, who plays the slide trombone with more energy than I have heard in a long time, was a delight to listen to. They performed not only in all three excellent shows, but also in the Cool Club lounge where they took the time to explain a little about the mechanics of performing together and passing the lead around during jazz improvs. The show singers even performed in the lounge. The final show, The Big Easy, featured the music of New Orleans and was the most creative show of the three. My favorite number was "The House of the Rising Sun" with four ragged wraiths in bat costumes following the singer around the stage.
The food in the Empire Dining Room was better than other Carnival cruises I've been on. Nice presentations, good variety, and the steaks were tender and juicy. The dancing waiters shtick every night was something I looked forward to, although if you had told me about it beforehand I'd have said it sounds ridiculous. We only had breakfast in the dining room the first morning however; as the service was so spotty we decided to eat on the Lido deck every morning thereafter.
The Spirit has a large spa with free access to an excellent steam room, sauna, and jacuzzi as well as resistance machines, weights, elliptical trainers, and treadmills for those who don't know that cruises are supposed to be a time out to relax. Unfortunately the spa services menu was just as over-priced as most high-end hotels in Vegas, $2/minute for a Swedish massage. Do your homework and reserve a massage in advance at a hotel in one of the ports of call for half the price or less. I talked to someone who even found a massage for two for $45 near Cabo Wabo in Cabo San Lucas. He also raved about the Kristal Hotel spa which is almost within sight of the pier in Puerto Vallarta.
The ports of call on this cruise were Cabo (2 nights), La Paz, Mazatlan, and Puerto Vallarta. Personally I can do Cabo in one day, but there's enough water-based activities and cheap Margaritas ashore to make it worth two days if you're so inclined. La Paz is not ready for cruise-ship prime time yet, I'm sorry to say. Be the first one off the ship in the morning for the 30-minute bus ride into town, otherwise you're likely to spend an hour standing in line waiting for seats on the second wave of buses. For the ride back I suggest you spend $5/head for a taxi rather than queue up around the block at the bus station. That said I'm not sure I'd want to walk La Paz again anyway. You don't have to get too far off the Malecon for La Paz to get boring. Perhaps the Weavers shore excursion would have been a better bet. In any case Mazatlan was much more to my liking. You can walk to old Mazatlan (or take a short taxi ride) and spend the entire day enjoying the well preserved architecture and art. Even the not so well preserved buildings are a joy to look at. There are many interesting shops like Nidart and Casa Etnika that are a pleasant change from the usual gauntlet of cheap, tourist junk that litters the pier side shops. Don't miss the market emporium near the Cathedral to see an interesting stew of humanity. In Puerto Vallarta we went on the Tequila factories shore excursion. Well worth the money. We were bused inland, away from the WalMart and the hotels that Hollywood built, to the Hacienda Doña Engracia and Leyva distilleries where our excellent guide, Amigo Raul, tells us they make small batches the old fashioned way, 100% agave and double-distilled. What is the proper way to end a toast with Tequila? "Arriba, abajo, a centro, adentro. Salud," then gulp it down—don't swirl it in your mouth, this isn't wine—count to three, take a deep breath, let it out, and feel the tequila warm its way from your belly down to your toes. Mañana.