The laptop you linked will run Orbiter 2010 quite nicely (especially if you use D3D9 client). FSX, not so much.
I have a 3 yrs old Lenovo G560 with a first-gen Core i3 running at 2.53Ghz, 4GB of RAM, Intel onboard graphics (not sure of the chipset). With D3D9 client in Orbiter 2010 and vsync disabled I have yet to drop below 80-100 fps. I wouldn't dream of loading FSX on mine. However, it did run FS2004 surprisingly well when I had it installed a few months back.
(note that the second laptop you linked is likely, though unconfirmed, running the third-gen i3, and would probably outperform my older chipset, especially from a power consumption standpoint)
Regarding Windows 8, most, if not all, of the gripes I have about it are purely surrounding aesthetics and functionality/productivity. This is based on personal use of my GF's Acer Aspire laptop.
My experience with it in a professional environment is a bit limited. But, what I've seen from a performance standpoint - t's blazing fast & very solid. A few in our IT dept. (including my boss) have been using Surface Pros for their primary machines for a few months now and they love them (and Win8).