I'm in the same boat. I have a Sub300 Searambler and it's amazingly comfortable. I'm worries that the Poseiden will be too big. I have a 6.75" wrist. Maybe the Poseiden will be a catch and release.Depends on wrist size. If 7" or under, I'd go Black Lung since the SUB300 case is so comfortable. Those with big wrists can handle the larger 1200T case size of the Poseidon. I have various Doxas, including the SUB300 and 1200T, and much prefer the feel of the SUB300 on my 6.8" wrist. That said, the 1200T is more legible due to the flat crystal.