I would consider ShadowPlay pretty useful. I've used it in the past, it's the easiest method I've found of recording decent quality gameplay.It still doesn't offer anything useful. The current driver update process works perfectly. And that is all I need, timely driver updates. The rest is garbage, aside from perhaps Shadow Play. Only reason I don't use it is because it is bundled with GFE.
A gaming computer will soon look like the typical user's PC. Full of worthless, contradicting start up programs and crap that just slows down their computer. Run software for your damn mouse, keyboard, a client for each game, and now to get timely drivers.
It's 2015 and I have 16GB of RAM and a 4 core processor at 4400MHz, I'm not too worried about a few CPU cycles for otherwise benign background processes. I cared about this stuff back in the days of single core processors but nowadays, unless you are experiencing actual issues, I wouldn't waste my time worrying about it. I have actually benchmarked my computer with all of my normal background applications running and without, there is no noticeable difference.