I think it all comes down to "trade offs."
Sergent's are Prototypical,especially when it comes to the shelf couplers whether it be the E coupler,F or H couplers. Then you do have to line up the Sergent's more.
No disrespect to Kadee,but I'm an all Sergent customer. I know people that work for Kadee, that use Sergent's in certain locations such as on their loco's.
Frank Sergent made the comment that he never wanted to be as large as Kadee,he wanted instead to keep his company smaller in magnitude and family owned.
Thanks again Frank,for listening to your customer's wants and for making sure they became available.