I ended up ordering this:
So now I have both products to compare. The tomtoc sleeve is a little bit bulkier, but I like it better because of the zippers.
Here are both sleeves next to each other:
And from the side:
The timbuk is a nice sleeve, but it’s strange in some ways; the flap doesn’t completely close so it doesn’t feel as “sealed” as the tomtoc. there’s also clips in the back that feel weird or at least useless to me.
on the other hand the tomtoc is thicker. now i can’t help but think i really need just a one-layer sleeve of some sort. no padding, just some water/scratch-proof thing so i can shove this thing in my bag without worrying about spills…
oh, and now i guess some will wonder what kind of case will fit the 16" too.
thanks everyone for the advice!