Which machine learning is the best? The five top machine learning methods I prefer are dimension reduction, regression, ensembling methods, natural language processing and reinforcement learning. Dimension reduction is important mainly because of its use in feature engineering and data pre-processing, where proper dimension reduction can greatly save time and space while keeping the most important information of the dataset. A good dataset that makes sense is just as important as having a powerful model, just as the saying goes – "rubbish in, rubbish out." Regression, being usually the most intuitive method to come right to mind, is both easy to interpret and fast to run.