For shooters or games with lots of trigger action I really like the configurable trigger distance. My hands are a little bad so reducing motion was worth the cost for me. The paddles are worth experimenting with; I like them for some games and dislike for others. The heft is also really close to the 360 heft which is one of my ideal controllers. If you have the extra cash to spend on a controller, I highly recommend this one. I use it for Steam as well.
Is it a necessity? Absolutely not.