I will not tell you which is the best, as everyone has their own opinion. However, you need to check out all ofthe booths available and make your own decision.
There are those that like the Mystic, Magic, Celebrity Tan, Cal Tan, Hollywood just to mention a few. Each of these have their own delivery system (some closely related to others). Some are made of plastic and stainless and others just stainless. You need to decide which is right for your salon and your area. Some give better warranties than others. Some use more solution
than others. There are just too many variables to say "which is best.". The one I like may not be the one someone else likes. It is the one you like and the one that fits your situation the best.
Just be smart and look at ALL of the possibilities, warranties and most of all the quality of each. Quality will give you an idea of longevity of the unit life. The longer it runs, the more money you make. The less breakdowns, the more money you make. Keek all of this in mind when making a decision.