My wife and I have AAA Premium or Plus, whatever it is.. And it has paid for itself over and over.. Between me having project cars towed between my house and my parents/in-laws and to shops and what not. I plan on adding the Motorcycle coverage soon. I would highly recommend it.
In regards to your question, Slime should work in tubed or tubeless tires (they sell it for bicycle tires). Fix-a-flat will only work in tubeless tires. And as mentioned, some places HATE the tire sealer stuff. Primarily because if they are going to patch the tires (on the inside) they have to clean it out and it's a royal PITA. I know it's not recommended, but for a tubeless tire, I would carry around a patch/plug kit. Some people would argue that plugging a tire is stupid. But, if that's what it takes to get you out of a pinch and off the side of the road.... I have plugged dirt bike and cruiser tires before without any issues. I had a plug in the rear tire of one of my bikes for well over 6 months before I replaced the tire and didn't have any issues. Just remember if you plug it to keep a closer eye on the tire pressure..