[spaghetti]

well if Miles recommends a gun, sure it must be a great gun.
But back to the initial question, which Omer, I can highly recommend them all.
Since you talk about hunting breams at rocky bottoms, take note that this is the typical spearfishing of Italy, and Omers are designed in Italy: this says it all.
I've used Omer XXV Gold, Omer T20 carbon mimetic, T20 Millennium, T20 allu, Excalibur carbon, Excalibur allu, Master competition, Black master, older T20, MB 30, and they ALL performed accurate, handy, manoueverable, durable and reliable. Just stay away of a gun called Omer Alluminum (yellow handle): it's not likely to last long due to galvanic corrosion of metal parts. All the other Omers are ok.
If you buy in a real-life shop (I mean: not on-line) buy the one that you prefer.
Now please let me too recommend a gun, if you have access to it: Seatec Gabbiano Open Elite 100 (open muzzle).