Both Yihi (SX Mini) and Evolv (DNA) are on par with each other, similar in analogy to buying a Chevy Cruz (cheaper, affordable, gets the job done, Yihi) to buying a Cadillac (pricier, better warranty, and better company backing, Evolv). I've used both brands of boards, Yihi boards in all your big name Chinese mods (Pioneer4U, Sigelei, etc), they just work, can handle a ton of abuse, and just stand up on their own, some times better than a comparable DNA board. I've also owned several, Evolv board, mods, Hana Modz DNA30, DNA40, Vaporshark rDNA40, Innokin SVD 2.0 (re-worked DNA20), Therion DNA166/200, and a HCigar vt75 (DNA75), all of them were consistent, great voltage signal, their TC in the later boards is beyond what other chip/boards can do, have only had one go bad on me needing shipping back, that being the Vaporshark (a lot of problems with the DNA40 boards as a whole group), their DNA75/166/200 boards have had very few issues, but the DNA250 looks plagued like the DNA40 was. It basically boils down to price, and warranty, Yihi being a China based company, most you'll see is a 90day warranty, but I have Yihi boards that have outlasted many another mod (IPV2, Sigelei Mini 30watt, IPV3, and Sigelei 150watt), where with Evolv chips if there are still board models available (example DNA40 devices) if the board goes you can still ship it to Evolv or the mod manufacturer and have it repaired, sometimes still for free 3 to 4 years down the road.
In the end it just boils down to price and warranty level you are wanting, on a budget and need a good all round gets the job done, go a Yihi, have a little extra cash and wanting a better warranty along with a better voltage output signal and better TC and programmabilty (the DNA Escribe software) then go with an Evolv DNA mod.