Variety!!! We have been using a mix of sunburst, cave in rock, and RC big rock. Big rock establishes like a lawn grass in no time flat, which helps get the stand started with less weed pressure while the others might take a season to stratify seeds/set roots. We've had stands 6'+ in the FIRST fall in the last couple years with this method. Cave in rock typically stands up well through heavy winters. Sunburst is local here, we prefer to stick to as many local ecotypes as we can (you wont here me recommend Miscanthus for example). Another we have been testing the last year or two is sundance, seems to have even a little better winter standability than even cave in rock.
VARIETY!