THe C7 is upgradeable, you pop off the back cover and can install up to 16GB of the fastest ram on the planet, and right next to that, a SSD drive of your choice. I bought the Acer and am glad I did. Already ordered the upgrades. Not that it isn't lightning fast ans smooth as it is, but as a gamer (who has ZERO inkling of using this Chromebook for anything of the sort, ever...) I cannot help but get under the hood and see what can be improved =)
I replaced my Samsung with a C720 and the unmodded spec improvement is easily recognizable out of the box. The Samsung would often lag if I was watching video on one tab or the native video player and trying to chat in another. Have yet to encounter the lag at all on the C720.
Only place the Samsung is better is aeschetics, but they're not as important as performance. Important, but not enough for me to go back, ever.