I forgot we're talking to the man who put the "sub" in "craigsub"
In a moment of weakness I just pulled the trigger on some non-HP B-stock M60 v4's, so assuming I feel up to carrying a pair of M60s up and down the stairs yet again I should be able to comment on (a) M60ti vs M60v4, and (b) M60v4 vs Ascend Sierra-1.