Ive been to salsa classes. I didnt like it. I like the dance but i think its usual salsa class set up (well every class ive ever heard of has been the same) is that you change partners every 5 mins. I really really hated it when you could see the next leering bloke was a sweaty, smelly, dribbling mess and i knew it was my turn next 
In saying that a club in town has a salsa night on a tuesday and its like a disco for all the latin people in the city. Its amazing going to watch them dance, the salsa is a lot more relaxed than the rigid style you are taught in class. Its more a 123 pause on the spot than a forward middle back middle step (you will see what i mean) 
occasionally a couple of show offs or professionals will get up and everyone will watch, it really is a great night to sit and watch with a drink.