If you like classic styling and the watch is to be a 'keeper' i would say go for the sub [i have a no date 14060m]. For me Omega's designs are too fashion conscious and change quickly to match the vicissitudes of style.
The sub has evolved slowly [like most of the Rolex line] and a you can see the DNA of the original models from 50 years ago in the latest model. A sub will never be out of style or fashion because it transcends these temporal concepts. A sub is 'the' dive watch - all others are just wannabes IMHO. The Omega will date quicker as its design is tied closer to the style of the time.
But that just my two cents - buy the one that makes you smile
Regards
Tim