Former SGS3 user here (non-neo, AFAIK). IIRC Samsung only managed one year of upgrades for it. The device had a, for that time, nice AMOLED screen and some flagship features. Custom ROM I ran on it (CM, probably, back in the days, or LOS) rather slow. And you get no baseband firmware/SoC upgrades anymore, since like 2015 or so. After this debacle I said never again Samsung smartphone. I gave mine away to Fairphone (they like to have smartphones of competitors to study design pros and cons).