Santo Rico is very big on technique and fundamentals (timing, proper arm tension, leading/following, spinning, etc). All of their instructors are good at giving back personal feedback and corrections during class. They offer structured cycle classes which help you build on previous classes. I have been a longtime student and credit them for any good salsa technique I have.
I have only taken Eddie's Sunday Intermediate shines class, and while there is not much individualized attention, I absolutely love that class. It is always challenging and fun and leaves me inspired. I also highly recommend his son's class. It is a lot less crowded, he gives great tips on how to make the shines look cooler and more dynamic, and he is very accessible for questions, advice, etc.
I have only been to Yamulee about 3 times. I would probably have gone there more if it was easier to get to from where I live. Their teams are among the best in the city, and their dancers look amazing and fast, so I figure the school must be doing something right.
I've only taken Frankie's body movement class once. What he can do with his body is incredible to watch. He doesn't say anything throughout the class; you just have to follow what he does. However, people have told me he explains more in his other classes. I'm sure if I took the body movement class on a regular basis, I would catch on to the routine and see an improvement.
The great thing about NYC is unless you are tied down to a certain team, you can take classes from as many instructors as you want! No school is going to be the best at every single aspect of salsa. You have the freedom to try schools out, and pick and choose what works best for you!