I couldn't get enough of that first Argentine try when I saw it live. The take by the full back was terrific, and the step and pace by Sanchez... The finish reminded me of Shane Williams vs the Springboks back in 2008 I think (going inside and then out). Considering the Pumas has so few recognisable star players I think they did remarkably well, and were only really killed off by a cheap interception try that took the game away from them.
I have to say, I think people sell Lydiate short. He always plays well for Wales, and I agree with you that Ferris is a better ball carrier (stronger, probably faster too) but I think the last six nations showed that Lydiate is a ferocious tackler.