Define "best dyno".
-Best shop to deal with?
-Biggest numbers from any dyno within 200 miles?
-Coolest dyno paint job?
-Best videos playing while your car is dynoed?
To me, a dyno is a dyno is a dyno. It should be consistent and the operator & shop should be decent to deal with.
The shop/operator should make sure they do the best they can to NOT damage your car in any way.
They should have the knowledge to make suggestions based on your dyno numbers as well as your goals.
Price should also be reasonable.