As man my two favorite artists, this is tough for me
I love the way Jim Lee drew Superman and Batman, they just look "right" to me
Reis does better facial expressions and his work on Blackest Night might be my personal favorite of all time
If I had to choose one I'd just go with Jim Lee though
Jim Lee is a much better artist. Before and after new 52. His vibrant colors and attention to details are strong and look amazing
He doesn't color his work, or ink it.
Scott Williams(inker) and Alex Sinclair (colorist) are his most frequent collaborators.