Since the Omega was recently serviced and is in "mint" condition we can assume it is close to new .
Therefore, I would ask myself 2 questions.
1) Would I rather have a NEW Seamaster or a NEW Aquaracer or a NEW Legend Diver.
2) Would I rather have a USED Seamaster or a USED Aquaracer or a USED legend Diver.
If one watch answered both questions that is what I would buy. If I got two different answers I would keep looking for a watch that I couldn't live without and get that one.
You can over think this by evaluating value, resale value, prestige, history, and a few other variables. If you do, the Omega would almost assuredly come out the winner. But if, deep down inside, you want one of the others then you really would be better off getting what you really want (value, resale value, prestige, history, and a few other variables be damned).
Personal opinion; It's better to decide what you want and find one that you can afford than to decide what you can afford and buy the first or second pretty face you see.