I heard non-touch is not sold in the US?
I got mine in Asia (HK), they have both S and M available. no replacement surfaces yet, but wacom should roll those out ltr.
overall I'm pleased with upgrading (i3 to i5, like you), but
a) surface takes time to get used to
b) check the shoelacing thread in this subforum. not a deal-breaker, but rather annoying and you should be warned.
c) I'm not selling/throwing my i3 out. just in case.
on the fourth day of glitchmas my painter™ gave to me
four random crashes, three broken brushes, two system hangups & one corrupted workspace