Darn Tough is top notch. The Darn Tough Merino No-Show mesh is my go to running sock for trail and road running, breathes very well, no issues with socks getting crusty or tacky during or after sweaty and dusty trail runs. I typically don't wash my socks until after my long run on Sunday alternating socks during the week. I also own both the Darn Tough 1/4 Sock Mesh and Cushion offerings, both in merino wool. I'm a wool/blend convert and prefer wool over poly for all my running socks for their ability to be worn multiple times and not stink or lose resiliency. In my experience the Darn Tough socks are equally as comfortable as my Smartwools, I don't really think they are necessarily better to the comparable Smartwools, I think both are quite competitive. The one thing I've noticed though with my Smartwools is the fibers pile much more, all of my Smartwool socks have this light merino fuzz which doesn't hinder the performance of the sock but definitely the appearance, this hasn't been an issue with the Darn Tough socks I own. But I'm sure this is subjective as to individual care, use and wear.
Depending on your conditions, needs, and activity I think the Darn Tough lineup is easier to navigate and select from for a wide variety of uses. Honestly, I get confused looking at the endless options of Lite, Ultra Lite, PhD, Outdoor, etc, etc offered up from Smartwool. The Darn Tough 1/4 Cushion in merino is a year round versatile sock perfect for trail running, hiking, and any outdoor activity you can throw at them really.