Sandler Sales is a brand of sales training develop by David Sandler which has been franchised around the world.
Aspects of it are counter-intuitive and if you are struggling to convert qualified prospectives into paying customers, I recommend that you take a good look at the Sandler approach.
It won't suit everybody. I know that some feel it is manipulative while appealing to be the opposite. It will make you think about what you're prepared to do to get a sale, especially a sale that you know is good for the customer and good for you.
Ther is no such thing as the best sales system, just the best sales system for you. It might be Sandler.