you see I thought so too until I tried both.
(http://i32.photobucket.com/albums/d25/jokerbloodz/sleip.jpg)
(http://i32.photobucket.com/albums/d25/jokerbloodz/valk.jpg)
HP and items are marked in a red box.
I know the difference is not much. but i've always thought of sleip giving me more hp supposedly than the valk. both have DL.