I've had my TNW ASR in 9mm for over a year, had it out a few times, put maybe 300 rounds through it. All 147gr subsonics, so in that respect I'll admit my experience isn't terribly relevant to your question.
As regards the viability of this model as a 'survival rifle' I'd say yes and no. Yes if you are a tinkerer, if you enjoy digging into what makes a gun tick and improving it. Polishing parts, refining shapes, replacing the mainspring with a Strike Industries flatwire AR spring seems basically essential, and generally holding its hand until it functions to suit what you like to shoot out of it, all that kind of stuff makes it a solid 'no' for anyone looking to buy an out-of-the-box, ready for SHTF survival rifle. Not gonna happen. But if, like me, you actually enjoy figuring out how to improve a gun which is essentially a steal at the current lowest Canadian price of $850 (G4C has them just in this week, a few other shops getting slightly differently set up versions for a bit more with apparently nicer grips and stocks), I'd call it perfect as a survival rifle. Very tidy little rifle. With both halves coming in at under 19" long for putting in a backpack it's eminently transportable, great for those times/places where you don't necessarily want to be perceived as carrying a firearm, such as in avoiding alarmed looks from other hikers while on your way to a shooting spot, or going shopping during post-apocalyptic zombie times and not wanting to have bad guys in the shadows looking to steal your rifle.
The parts are very well made, just not finished very smoothly. Trigger needed some work to smooth it out, now it's awesome. Feed ramp on the barrel (it's actually stepped, more like 2 feed ramps) needed a bunch of polishing and rounding of sharp edges to prevent catching the odd JHP tip, now it doesn't do that. The spring problem seems to be basic enough; they cheaped out on a do-all spring which can't reliably cycle on some lower powered ammunition, so FTE/FTF issues are far too common - swapping for the Strike spring fixed that, it just works well. A bit of investment in labour and parts made this a gun I'd very much trust to shoot when I need it to shoot. But I work on stuff for a living, primarily making violin family instruments work better, but a life-long habit of fixing things makes it relatively easy to tinker with a firearm until it's functioning better. My years of modifying and sort of building airguns made that easier as there's a surprising amount of crossover between them.
All that said, you will likely enjoy the Ruger. A friend with one absolutely loves it, says it cycles everything he feeds it. Feels solid, very good feeling rifle in the hands. Takes down small enough to slip into a sling pack alongside other necessities. And the after-market support does seem better. Finding TNW spare parts is a bit challenging. I may end up machining myself a spare firing pin, as so far TNW hasn't bothered responding to my requests to buy one and no Canadian supplier stocks them. I do have a couple of spare takedown pins and a barrel nut from Hi-Cal which is neat, as it's easy to imagine losing a pin or wearing out the aluminum barrel nut through assembly cycles, but the firing pin is sort of central, be nice to have one to throw in should it break or bend. TNW doesn't seem to notice my emails from two different addresses. And while Hi-Cal has more TNW stuff than ever, they still seem not able to get some parts.
