Originally Posted by
UNITED863
21J (preferred for overhead space), 21A (next best) on the domestic 763.
Add a glass of wine+sleeping pill+blanket and you have a nice nap. Better than first on that airplane.
+1 If the objective is to sleep well the entire time (without getting up to use the lavs), as these are better than what F can offer.
However, if you are in F there is nothing better than 5 E/F. Being in the middle, you don't have to worry about anyone waking you up to go to the lav. Also, you don't have to worry about waking someone else up to use the lav yourself. Being in 5, you can put your briefcase/smaller carry-on behind your seat to allow you to stretch out your legs. However as noted, row 21 in E+ has much more leg room than anything F can offer.
If you are tall and thin, go for 21. If you are short and wide, go for 5 E/F. If you are in between, try each to see what works best for you. Do note that IME 5 E/F tend to be available longer than 21 A/B/H/J. How far in advance you book and when your upgrade clears may impact your ability to secure the seats.