Recently, I started watching 'Shark Tank' regularly and was very impressed with Mark Cuban as an investor / judge. He almost always, listens well and talks the last. His comments and rationale for 'yes / no' decision are very insightful. Mark focuses on all the right things to make an investment decision: quality and commitment of founders, product-market match, proof of concept and then interestingly, some heart, emotions and theme.
I explored more about him - his blog is equally gripping. Of the ones I read, I liked Stock market - where he lays out 'supply demand' dynamic of stock markets and how inefficient they are, and Fox News Should Watch Dancing with the Stars, where he points to an interesting human psychological trait - to save your hero, but ONLY when required. Still trying to understand his views on politics..