I will echo what Brent says, no downsides in practice and none in research before started to use them.
The difference is dramatic, starting when you put the rings on the pistons, they go easy, and when using a tapered compressor, you give them a light shove with your thumbs and 1mm/2mm combos almost carry themselves down the hole. 1.5/3.0 packs are not that much different. I am finishing a 462 right now with 1/16 rings, it'll make power and nothing wrong with it, I did those with the same compressor and they went fine, but the difference is significant.
It's not ring design either because I have used Hastings and Mahle in all three sizes and it's consistent regardless of ring. FWIW I have only used std tension oil on all. As far as wear being better, research says yes, but I haven't had one apart.
As far as DSS, haven't used them, but I would assume better than a Speedpro, I'd look at clip design, pin weight,overall weight, then start measuring and see how consistent dimensions are, but I also think Racetec with a 1.5/3.0 or a 1.0/2.0 is hard to beat, and if Mahle has shelf pistons, also a very good deal for what you get. I wouldn't mine seeing what someone finds though, if the price is right and it's a good piston, always good to have options
Back to the rings, one bit of advice, I tried many years ago to use my old favorite wrinkle band compressor with a thin ring, don't do it. Buy a 40 dollar tapered. I also have a nice set of Snap-on plier-type with multiple interchangeable bands, it'll work with the thin rings, but the tapered compressors are where it's at. The old two thumb shove and it's in