Watchfinder is a good bet. I'd say save for a used one if possible. Not sure how Omegas hold their money but sure would be good purchase.
I bought a GMT II from Kuala Lumpur about 5.1/2 years ago and its still working now, was about £75 as I really liked the watch at the time and wanted to see how it felt size wise compared to my Tag Heuer Aqua Racer. In 2014 I was fortunate enough to be able to buy a new blue/black one and its been my everyday watch ever since. Managed to buy it before they got into demand. The fake looks great although the crown stopped screwing down. Very hard to tell the difference with a good fake but you always know its not real. I took it to Cape Town on holiday as didn't fancy wearing the real one but other than that it now sits in a drawer.