This is an obsolete choke tube system Mossberg used on mostly very inexpensive bolt-action shotguns. I have such on a very early 20 gauge 500 pump. Finding the tubes is quite difficult. The only reason I have the barrel with that choke is because it was on a the shotgun when it was given to me as a gift.
About the only place you can find info on them is here:http://www.havlinsales.com/
Virtually any choke system is better than this. In addition to being as homely as a mud fence, the C-lect choke has the threads on the outside of the barrel where they are very easy to damage.
Don't think I would agree with much of anything you said except that the C-Lect choke is no longer in production. I suspect that is because the current Accu-Choke which uses choke tubes is less expensive to manufacturer.
It is very similar to the current Poly-Choke system and the only threads on the outside of the barrel are covered by the adjustment sleve.
I have had a few over the years and I think there is still one in the family and it still performs very well. Ugly is in the eye of the user, and performance and the convience of quick changing choke settings can easily make something look a whole lot better.