I too have not had a Diver, but I like my Sophia's almost enough to say I love them (but not as much as I love my Dripper Pro's).
I was on a waiting list for Diver's at a favored US vendor... and waiting... waiting... and more waiting until I got tired of waiting, changed gears and bought my Sophia's instead. In my case I waited so long because I was trying to support a vendor that I had become friends with and who had built me a custom tank (that turned out to be just for display). But I hated the other carto tanks I already had because I have always hated carto's and it was well past time to do something about it. For some folks it might be the price point that makes the decision for them. The Diver's are after all cheaper, $20+ cheaper, can be bought from US vendors when in stock for cheaper shipping and faster delivery.
So I am another one with a fair size supply of carto's I will never use again, a $40 carto punch I will never use again, and my first IBT carto's tanks that I will never use again. The later is just a personal thing though... lots of folks like their tanks - I don't.