Something I have noticed for home users of the Pro Controller to beware of:
If you are stupid and lazy like me, you might also have a tendency to leave the controllers plugged in, cars on the track and power on when you are not using your track for say an hour or a day... DONT do that with the pro-controller! The electronics in the handle gets hot when the brakes are being applied for a long time, and you will return to a toasty hot handle! It has never felt dangerously hot, but this is obviously an even less safe thing to do than my normal (no electricity flowing in theory) practice.
Let me just add now - since this all sounded a bit more sensationalist than intended:
after an hour, the handle feels a little warm, enough to notice, but not to be alarmed about. After many hours, it feels quite warm. I am talking about low riskd and probably shortening the lifetime of some of the components in the controller, not instant burning down of the house. The controller has never got as hot as the transformers, for example.