Someone ran a benchmark program and found out that in some tests, Samsung SSD was a little faster than the Toshiba. They would have never noticed this difference had they not run a benchmark, as both are crazy fast and in everyday use you can't tell the difference. Perhaps if you copied a very large file side by side one would finish a second or two sooner. So what?
Well, for some folks this was unacceptable. They had to have the "faster" SSD no matter what, since they considered the other one "inferior". Sigh. Same thing with the screens. Someone said the Samsung was better than the LG. Someone said they liked the LG better than the Samsung. Some folks rushed back to the Apple Store to return their "defective" Airs because they had an LG screen. The first post I linked you to was my attempt at showing there really is no difference worth obsessing about.
Fact is Apple doesn't advertise the brands of components inside their Airs. This is not an option you can choose when you buy. You can pick screen size (11" or 13"), processor (i5 or i7), amount of memory (2GB or 4GB), amount of storage (64, 128, or 256GB) and that's it. it doesn't matter what brand the screen or SSD are, the Air is a solid performer.
Buy an Air, enjoy it, and be confident in Apple's ability to produce a quality laptop with components that meet the standards they've set for their systems. And if you have any problems with your Air, rest assured Apple stands behind their products and will fix or replace any defective component or the whole laptop itself if necessary.
Hope this clears it up. This, however, is MY opinion. Others will certainly chime in with theirs.