The 570m is roughly 15% faster than a 560m. If gaming at 1080p is your primary focus I would go with the 570m, unless you really need the extra storage and BR drive.
BluRay is not crucial and the 1.5TB is probably overkill versus a mere
I'm trying to find comparative data on the 570m vs the 560m but it's so new there's not a lot of information out there. I am running across an apparent issue of minimal driver support (at the moment)
for the 570M.
One last thing, as per Newegg it seems that it's only
MSI who are equipping their laptops with the 570M, and from what I've been reading about the build quality of MSI machines I'm not as comfortable with their products as I am with ASUS.