Both should be good guns - the Cayman is a higher spec. model I believe (I believe Apache < Comanche < Geronimo models - no disrepect to our Native American members) and probably more expensive. If the pictures of the water above are typical, the water there is very clear and 100cm should be fine. And on day/locations were visibility is poorer - use the old 60cm speargun.
My personal preference would be the Cayman - I like Omer stuff. If Cressi is your preference, consider also the Comanche & Geronimo models. I would think the Cayman & Geronimo are at similar product levels (& price). [Omer Excalibur or simpler Caymans are cheaper Omer options, perhaps more comparable to the Apache.]
My personal preference would be the Cayman - I like Omer stuff. If Cressi is your preference, consider also the Comanche & Geronimo models. I would think the Cayman & Geronimo are at similar product levels (& price). [Omer Excalibur or simpler Caymans are cheaper Omer options, perhaps more comparable to the Apache.]