Just bought an Evo 15cc. Anyone had experience with these? I have heard that they must be broken in on the bench. Is that so?

Nope!
Pete

I don't think a bench break in is required either. What I found on the 10cc engine that uses a similar carb, is that a few minutes with owner's manual in hand familiarizing yourself with the set up/adjustment of that carb will be worth your time. Though it may look familiar to glow users, from a practical standpoint It's different, especially the low speed.

Great little engine. No bench break in required. Just be gentle the first two flights.