I'm not sure having a choice for air traffic control is a good idea. UK does of course have a large number of ANSPs who compete to provide ATC in the airport's environment and even has some bits of airspace where you can get an ATC Service from a choice of providers but by and large I'd like one ANSP to be controlling all the aircraft in a particular bit of sky. How you chose that ANSP & fund it is a political decision.