Most contracts exclude consequential loss arising from performance issues.
The "SS" kegs with only a top opening in the other thread are quite common place but are specifically designed to be used with a top mounted CO2 driven dispensing system, which is obviously different from the CS lined kegs bought pre-filled and also available new from some homebrew suppliers and which are fitted with a bottom tap since that how the beer is intended to be dispensed.
As to the question to the 'SS' keg supplier, better... "Are these kegs stainless steel as advertised, and not internally plastic lined carbon steel?"
My own theory about why the CS lined minikegs produce a metallic taste is that they are only really one trip and not intended to be used under pressure (although your experience suggests otherwise, but maybe that's an error) but if they are re-used and pressurised by homebrewers it flexes the joints, the thin lining cracks and that allows beer (under pressure) to access the CS, which it then corrodes. And within manufacturing tolerances, and differnent handling and different internal pressures used by different homebrewers, some kegs will fail early and some will last for a few brews before the metallic tatse kicks in. And perhaps some may not fail at all.
