Over the years I've known about a dozen ATCOs go for full time commercial flying and they never looked back (one or two comment an the long hours they now endure). I have also known some, myself included, who gained commercial pilot qualifications and found themselves unable to leave the comfort/security/lifestyle etc of ATC. There are also some, who do both ATC for a day job and commercial flying on some days off. I've seen controllers flying around in HS125, Learjet, ATR, King Air, Islander etc with no intention of leaving the day job.