Use the search feature to find threads on this topic. It has been discussed, debated, argued, .... over, over and over again. After you read many threads, you will have to arrive at your own conclusion. "Popular" as your question asks is not the right question, rather what you want/need to do, how you wish to work, how you wish to be paid, what kinds of customers and their demands, what kind of equipment you wish to invest, etc. You will see from existing threads opinions range widely. There may be firm answers to some questions, but this question isn't one of those.