I think what I really like is the litheness of them. A lot of the Warhammer elves seem too burly to me, especially the high elves, but even now the Black Guard and Executioners went a bit that way. Elves should be stick thin and look like they could bound right over your head and cut your neck open on the way over. That's what these look like. Plus the nice variety of poses on them is good.
The the last 2 incarnations of witch elves have been very good for this and whilst the old wood elf range had a lot of great figures, some were a bit muscular for my liking. Wardancers for one... Poses great, but a bit thinner seems more approproate. Part of what sets them apart from humans to my mind.