One word, Tradition.
I have had them both but really prefer the traditional crown over the comfort curve.
There is something about a traditional looking Conga that just captivates me, the crown the bands, not to mention the natural skins.
I did find, however, that the comfort curve is more comfortable, not to mention, that in some cases the rivets on a traditional crown sometimes become loose and so there is a need for repair.
I believe that you will find that most of the Congueros that have been playing longer would lean more towards the traditional Conga.
My 2 cts.
Cheers.
K.C.
See attached Image showing a classic example of traditional congas, Requena and Skin on Skin side by side.
I titled this picture "Two legends meet"