In today's computer market, I would put a Perdix AI first on my list, not that you listed that one. Second would be the Teric, and third the Aqualung. (I prefer user replaceable batteries that are easy to access).
Battery changes are a pain on the OCi and if given a Suunto I would sell it...just don't care for them at all, but many seem to like them. I am not necessarily a big fan of the PZ+ algo, but could live with it if my choices were that or a Suunto or OCi.
If you really want a watch-sized computer you could also look for an Oceanic Atom 3.0 / 3.1. Better choice than the OCi in my opinion and less expensive as well. I believe they are discontinued but that doesn't really matter much to me.
Maybe check into a TUSA also. I am not sure what their current models are, but they have or had very similar models to the 450T and the Atom.
Or jut get a Perdix AI and be done with it. It isn't THAT big.
Good luck and I hope you enjoy whatever you do choose.