Best virus, spyware protection.

For a long time I used both Bitdefender and Malwarebytes. I recently dropped Bitdefender and figure I'll give Microsoft Defender a shot. I've been hearing that it's much improved. I also run the paid Malwarebytes. It's my understanding that the difference between free and paid Malwarebytes is the paid version runs in real time and stops the threat before it gets into the system, while the free version has to be initiated by you after the fact. If I'm wrong about this guys help me out. I haven't had an infection in years(knock on wood).