My opinion is that the Advanced Powerbase (APB) with computer software (RCS64, SSDC etc) is the better system. Add wireless controllers and it’s as good as Scalextric digital gets - at the moment. However, ARC Pro is a fabulous entry-level system and costs a fraction of the price of the APB + all the add-ons. And it does almost as much... especially with the Magic app. I suspect, in time, ARC Pro will develop into another excellent system, perhaps offering even more than the APB?
My advice to current digital racers using the APB is that they don’t need to switch. For new digital racers - or digital users wanting to upgrade from the old 4-car powerbase - I would suggest ARC Pro as it is very good value, has great features out of the box and is at the start of its development process. I now use ARC Pro at home and a full-on APB system at my local Scalextric digital club.