I bought 2 Kel-Tec S2Ks and 2 new TNW aeros new. The keltecs were both gen 1. My opinion of the S2Ks is that they're absolute garbage. 115 grain ammo was very unreliable. 124 Blazer brass was extremely reliable, no stove pipes, light primer strikes, or FTFs like I had with rem UMC. The safety does engage with every round fired. After all issues are sorted out it'll be up for sale. The only real thing it has going for it is that it folds in half.
As for the aero rifles. 1 was flawed out of the box and was self destructing with every round fired. The charging handle was slamming into the receiver. The warranty center wouldn't replace the rifle either. The dealer eventually replaced it. The second TNW is absolutely amazing. Complete ease of assembly and disassembly, well built, aluminum, vey accurate and reliable, I just wish the charging handle was on the left hand side, or could be swapped like the ejection port. Until then, it's not quite there for me, but so close.