5 years ago when they were trying to sell this thing for over $200 it wasn't worth it, but at $90 and after reading that they fixed issues preventing it from competing with normal network cards I thought I would give it a try.
All I really have to say about it is that I really don't notice a difference. I still keep it in because if I take it out and experience lag I always start thinking I shouldn't have taken it out, but I'll admit that this is probably nothing but a placebo.
Back in the day offloading networking to a separate piece of hardware was a great idea but nowadays when pretty much every CPU is capable of running 4 or more threads simultaneously, this is no longer an issue.
The only other reason to get it would be the application bandwidth throttling in the network manager, but the drivers are a resource hog and I don't really use them. If you think you would then go for it, otherwise save your money.
Intel Core i7-5775c, Asus Maximus VII Formula, Win 10 Pro
EVGA GTX 1080, Corsair 2x8GB DDR3-1866, Corsair AX860
Corsair H105, WD Red 4TB x2, Creative X-Fi Titanium HD
Samsung 850 EVO 1TB, ASUS ROG PG348Q, Corsair 450D