i would say an '8 is certainly as strong as a millie, i have never liked the thin liner on the millie myself, and the millie has but 1 liner vs 2 for the '8, so i would say theoretically the '8 would be a little stronger, yes i know that very few millies have lock probs, still though w/those thin liners.....i certainly like the aesthetics & grip a lot better on the '8.
i would say the '8 is as good as any of them for HD use barring something like a strider AR.
great knives BTW, i have 2 a SF/EKI and a specwar custom w/a zero bevel grind blade, the specwar is my fav edc for the past couple of yrs.