I dont particularly care for the cobras, I like my Channellocks better. That said, they arent what I'd call a gimmick type tool by any means. It all depends on how a person uses their pliers and what they are doing with them. (IE using pliers instead of a pipe wrench, ete...)
No set of pliers is perfect for every job simply because everyone uses them differently. For instance, I've got three 6" slip joints at work and each has a slightly different jaw style, wide/narrow/"normal", so each gets used for specific things when the need arises.
I have both Channellock and Knipex (Craftsman) in 10" and the cobras are the only ones that I managed to pinch fingers with (opposite of everyone else). The cobras are quite a bit slimmer in the jaw by comparison, but there are times where the jaw style on the Channellock is better (more surface area). Six vs. 1/2 dozen.