My understanding is that there's less of a performance difference between this year's MBA's SSD brands, each having pros/cons, whereas in previous years the Samsung was much better.
People have been finding significant differences in the brand of display used, though, with Samsung generally considered to be better than the LG display used in some 2012 MBAs, though the difference can be mitigated to an extent by not using the stock colour profile.
I have Samsung for both my display and SSD in my mid-2013 MBA, but would've been happy enough with a Toshiba SSD this year, as don't use FileVault.