That is a vast question. The more we know about what applications you use, what your aspirations are, and what your experience is, the more useful information we can give. JAWS is more often used in employment settings. Some say NVDA is better on the web, I don't know enough to make that comparison. JAWS is somewhat more configurable, with more settings. But NVDA is a very viable program now, and if you do not need JAWS for work, NVDA may well meet your needs. It is free, but they always ask their users for optional contributions of money.