most "purple" purple Fagus sylvatica
I've always liked European beeches - they're so-so around here, plenty of nice specimens but we're probably a tad hotter/more humid than they really like.
That said, they usually grow OK.
In a hotter summer climate, which of the F. sylvatica cultivars with purplish leaf color have the "truest" purple that stays around longest (not turning muddy in summer)? I'm more interested in those with a standard growth form as opposed to fagistate or weeping.