Modelers tend to buy whatever engine is deemed successful at their field.

Some things that came out during the great "OS Peeling era", although I'm not absolutely sure if they are true:

TT uses a thicker ABN plating than OS so they didn't peel.
Magnum is one of the few true ABC's (which may no longer be true).
OS went to a different process.
Much of the peeling was due to leaned out engines using low oil content fuel.

George