Excuse a long retired Old Fart having the temerity to voice his opinion. I did both Area at LATCC and Aerodrome/Approach in my time. I thought working in an ATC Centre was the Air Traffic equivalent of working in a factory. At airfields I felt closer to aviation - back in the day, depending on the airfield, you could get to meet all sorts of people outside ATC and wander round terminals etc. I guess since 9/11 security measures would have put paid to that. As Equivocal says, airfield qualification means you can change employer if you so wish - in my time places such as Newcastle, Jersey and East Midlands etc were considered good places to work.
However, my son who is an ATCO at Swanwick wouldn't work anywhere else.