One thing that I discovered recently which surprised me (while taking the Udacity SDC)is how effective and resilient these "older" ML algorithms can be. Neural networks was always my go to method for most of my classification or regression problems for my small side projects. But now I learned with the minimal dataset I have (<5K samples), linear regression, SVM, or decision tress is the way to go. I got higher accuracy and it's about 10X faster in terms of computational time!