if you have never tried one, and are getting tired of the cruising, go for it!! The magic feeling of the AI wristband is very nice...to have waiters bringing you free drinks with more frequent service than you can get around a crowded ships pool is excellent...swim up bars are fun too...did i mention the free in room mini bar...riu resorts offer liquor dispensors in all thier rooms. Can you tell i like alchahol?
The food can be awesome at AI's but the dining room on ship is fancier. I found the entertainment to be a little less varied at the resorts but i stay at the more economical resorts, it may be better at one of the 5 star places. Most of the excursions are fairly cheap. All the resorts in mexico have activity desks or people that can book your excursions from your resort...but unlike a ship thats the only thing you get charged for...if you stay on the resort, you can do anything but make long distance phone calls and you will not have a bill when you check out. (awesome feeling) the workers at ai places are well paid and tipping is not required. though we tip the maids (at the end) and bartenders (at the beginning)
there is allways someone cleaning or improving on the property. My brother smokes and as we shot a game of pool he put a butt in the ashtray, i swear in less than 2 minutes a girl appeared with a mini vac and removed it and fluffed the sand in the ashcan. service was just as outstanding at the pool or even on the beach! This awesome service is standard in mexican AI resorts, even the cheap ones...Resort amenities are listed and pictured on different sites with travelocity and some others offering recent reviews as well.
There are some that are more family oriented than others so i'm sure you could find one to keep your kids entertained. we have made a few international friends at resorts, like on a cruise everone is friendly and relaxed for the most part. Be aware some resorts look the other way as far as european sunbathing goes, so your son may want to hang out by the pool and beach all day

at least until he sees a grandma going topless

that sortta ruins the whole thing.