I can give a nuanced view as well. In the past month or so I have tested Malwarebytes 3 times in total. On the first test it missed all 5 samples and my test system was encrypted. On both other tests (since I was in a better mood and didn't want to be too tough on it) it blocked 7/10. None of them were 0 days. Malwarebytes has implemented a form of machine learning called anomaly detection - this is where the solution gets trained with "clean" files (usually a set is divided 60:20:20 for training, evaluation and testing). It then establishes a baseline or sense of what's good and everything that deviates from it is considered malicious. It gets flagged as MachineLearning.Anomalous.xxx, where xxx is the percentage of deviation. It's all cool, but works only on PE EXE files and nothing else. Malwarebytes doesn't use reputation and their behavioural blocking, signatures and heuristics are not the greatest around. Its exploit and malicious website blocking capabilities are great, but not enough to compensate the lack of everything else and exploit prevention is now built-in to Windows. In the light of all that, I would not even use Malwarebytes free as a second opinion scanner, leave alone paying for it. There are free products, much more effective.