I'm having trouble pulling up those links, tried hours ago and same now. Anyway, assuming the only difference is hammer forged vs. button forged and $50, I'd pay the extra for HF. Probably not terribly important but I think the process results in a stronger and better machined barrel. Accuracy can be better too but I haven't noticed that comparing my HF AR (lightweight) vs. my button barrel AR (HBAR).
Since the LW barrel is much thinner than average I felt better going for hammer forging (in my Daniel Defense barrel).
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together. You'll remember the quality of a gun long after you forget how much you paid for it.
US Army 1966-69, VFW Life Member, Retired Geek