Here's a slightly different take (than above).
Whiel I like ARC gar, especially their latest big monos, and their ref pre (whatever the number), I cannot -empirically - place them at the same resolution level as the big Boulder pre (2110). That said, I agree with @ghdprentice regarding the sonic similarities between ML & Boulder albeit, from what I've heard ML is slightly more strident up high than Boulder.
As far as resolution goes, Spectral pres have always sounded to me to reach a hgiher level than either ML or Boulder -- if you go for that sort of thing, that is.