I've yet to find a cob that can give me a great smoking experience! But, I've found many cobs which smoke adequately and properly deliver taste and nicotine. Cobs are very utilitarian for me. I consider them to be disables used primarily when in the field, camping or fishing. Very practical but, aesthetically wanting. My opinion only of course.
A pipe has to fit my fist and my eye or else, no matter how well it delivers smoke, it will not provide a great smoking experience. It's akin to dining at a 5 star where the meal has been plated poorly. For me, if the eye is not pleased or, if the pipe is awkward in the mouth and hand, I will not get a good smoking experience no matter how well the smoke is delivered.
Most of my pipes during the day are purely for the nicotine. My evening pipes? Then, they are making a substantial contribution to my pre-bed routine with a good book and beverage. The pipe makes the book and the wine better. Just as the book makes the pipe better. Or, the wine makes the pipe tastier. It all has to come together for a nice evening smoke, the aesthetics, the blend, the book, etc. Meerschaums make up the vast majority of evening smokes. Any of my briars would suffice though. A cob? Rarely, only while camping, accompanied by a spectacular storm or sunset.
But, again it all boils down to what the smoker expects and requires. Purely a subjective matter.