I do like Bexley pens. And one of my favourites is the Poseidon. Two of mine are shown above - one in coral, and one in tortoiseshell. The tortoiseshell is a regular, while the Cardinal Orange is a Poseidon Magnum, slightly longer (five and a half inches).
The Poseidon is a nicely stubby and chunky pen. I suspect it takes some of its lines from the classic Pelikan 100 / 100N, though the filling system on most Poseidons is cartridge/converter rather than piston.
The Poseidon went through a couple of iterations: the second generation of production pens was available till quite recently, and I believe Bexley was fairly active with custom productions as well, as well as the larger Poseidon Magnum model. Bexley also created some lovely limited editions with Chatterley Luxuries, such as the Rosso Verde, but these are very limited editions (around 20 pieces) and I haven't tracked one down yet.
The gold furniture isn't too blingy, but the double cap band and twin barrel and cap top bands together with a cravat-style clip give the design a lively assertiveness. he fit and finish is good, though I note that the translucent material of the tortoise hasn't been polished on the inside of the barrel, where the turning marks are evident. (One day I'll get round to polishing it myself.)
My tortoise has a 750 gold nib in medium; it writes wet and wide, and while it's not vintage flex, gives a fair amount of variation with pressure. For note taking I prefer the orange pen, with a fine steel nib that is really crisp, but writes nicely wet so that it skates across the page nicely.
I don't see these pens too often on the second hand market, but when I do, I usually try to grab them. They are as robust as they look, and I've never had buyer's remorse with them as I have with some other Bexley models.