they said this is what they used on one car
Meguiar's Gold Class shampoo • Optimum polish • Klasse AIO polish • Pinnacle Souveran sealant
now, there's no such thing "Pinnacle Souveran Sealant"... there is only Pinnacle Souveran Wax, which looks great but lasts 2 weeks at most.
i looked through their gallery, and they use some good products... only thing that i didnt like was that they use optimum polish, which is not usually regarded as a "great" polish... i would try to find someone (if they are going to polish your car) who uses menzerna polishes. in the detailing world, those are the top of the line polishes (i use them myself, and i swear by them)
i guess it depends what type of work they will be doing to your car, if you would want polishing or just a wax job... pretty much anyone can wax a car, thats ot hard to mess up, but you have to be careful when you let someone polish your car, because it might look great when you pick it up, then a few weeks later when the glaze/wax/sealant breaks down you could end up with buffer trails all over your car.