Who doesn't love D. polytricha, and the fussier D. mollissima and D. longisiliqua? I actually have grown these pretty well for a few years in this or that perfect little microclimate. But Draba rigida pays rent. This makes as dense and hard a cushion as any Dionysia, and seems to grow with impugnity in almost any microclimate in a classic rock garden: I have it on slopes facing every direction, in crevices, in hot spots and in quite deep shade. No matter where it is placed it seems to settle down, and then year after year, decade after decade, just gets bigger and bigger and better, blooming for much of the spring and setting copious seed! It doesn't get much better than that!
I think we can thank the Czechs once again (probably Josef Jurasek) for reintroducing fresh germplasm of this fifteen or so years ago which gave the plant a new lease on life. A big reason why we need wild seed collection!