If the angled sleep will be a problem for you and you can snag a bulkhead J seat then I wouldn't bother with the extra miles for F if it's not on the A380 [agree with shuigao]. At 5'10, I find the angled sleep okay because I prefer sleeping on my side but if I were to lie flat on my back it would be annoying since my feet have a hard time fitting (US size 11) [or maybe it's just me haha].