The Nightwish version is lovely, but this one is completely intriguing. It has a totally distinct and unique feel and groove; it has more of a bluesy or jazzy (or perhaps funky) feel, perhaps because of the syncopation, and is less hurried. The percussion fits better, in my opinion, and the electric guitar is more melodic. This arrangement is really refreshing.
I am so glad that Tuomas loves Howard Blake's soundtrack for The Snowman which resulted in Nightwish covering the song which resulted in this ultimate version being created. :-P I did hear this version first, which may have tilted my favor a bit. ;)