Are a hell of a lot more reliable than the ones that replaced them. Many NATS people would prefer to revert back to the old headsets...
You've got to remember that Oxford never has had radar before so, although in my opinion they don't have the commercial income to justify the cost of either option and never will...
NikNak - Oxford have aspirations for a huge increase in traffic - possibly using the Olympics as a springboard. If they get their way (bearing in mind they do not have the same Local Council restraints that have hampered Farnborough), then they will have the income...