Can anyone inform me?
That's a bit like asking which is more colourful, red or green.
Both are equally prestigious.
They are of the same stature for most funding purposes and promotion. I doubt very much someone would nitpick which one is "better", considering how difficult it is to get published in either one.
Equal. They have about the same impact factor.
IIRC, as it was explained to me a few weeks ago in AP Bio, Nature is the European equivalent of Science, and both are equal.
Separate names with a comma.