I've been reading Edward Snow's single-volume revised edition of his translations from Rilke's New Poems, and I'm surprised to find myself more impressed by the poems in Book One than by those in Book Two--surprised because the second volume begins with the poem that is deservedly Rilke's best-known short lyric, "Archaic Torso of Apollo." Unfortunately, the volume goes downhill from there. That's the danger of opening your book with a masterpiece. But I think the problem with the second book goes deeper. Compared to the poems of Book One, with their giddy transformational energy, their seemingly unlimited stock of metaphors, their wildness and freedom and daring, the poems of the second part seem more subdued and deliberate--even, at times, exhausted. Book One reads like a fearless flying leap into the future of poetry; Book Two is a more careful and craftsmanlike performance. If in the first book Rilke is conquering new territory, by the second he's already an old seigneur, surveying his lands and putting up beautiful buildings.
As to the hopelessly complex question of the quality of Snow's translations (a question that I, a non-reader of German, am completely unqualified to comment upon), I will say only that I find Snow's versions of Rilke a bit too prosaic, perhaps too literal. Stephen Mitchell's translation of "Archaic Torso...", for example, is clearly superior as a work of art to Snow's translation of that poem. I also find Mitchell's translation of the Duino Elegies superior as poetry to any other version I've seen.