If had them both, owned a 150 for years.
They're "different" in terms of how they do it. The main one being the CS have a VERY moist environment. That works well for a lot of things, like briskets especially
I like the FE for chicken/ribs becuase you get more of a crust.
You can get in on the CS, you just have to open the door and let some moisture out.
We've talked about them a number of times, try different terms in your search. CS is generic, try model #'s. I know we've talked about it, don't know why you haven't found it in the 100,000 posts
The questions I have for you would be what are you cooking and in what quantity?