I did 18E for the first time recently on a transcon, on a 321/Mint. I would take it again over row 6 since you can keep bag handy under the seats in front, and you get two slots basically (underneath 17D and E). Tiny window though, so if you like looking out, it's not as good as other seats. Also has a small single-bag overhead compartment, so if you're boarding in one of the early groups, you get that for yourself.