A
Nature Affinity: Lightning
Jutsu: All his jutsu Have to do with his Lightning Armor enhancing his crazy strength and reflexes. They are all wrestling moves, so basically taijutsu like Gai. Yes, whoever said that he was the same speed as Minato, that is true.
No Keke Genkai (SPELLING?)
Hot-headed, which shows his quick and powerful fighting style.
Finally, along with his great strength and speed, he appears to have great stamina with having his lightning armor on continuously against Sasuke.
Gai
Nature Affinity: ?
Jutsu: He uses taijutsu just like A. He is quick like A, but does not appear to be quicker. He is physically strong, but it appears that A is stronger. Gai does have the eight gates, and it appears that A cannot use them. The Daytime Tiger jutsu (I'm sorry that seems like ninjutsu than taijutsu, come on Kishi!) is very powerful and would probably seriously hurt A.
No Keke Genkai
Fiery personality that is confident and determined, and fights quickly and powerfully too.
Finally his stamina is great too.
VERDICT
It would come down to stamina, and strength in this battle of taijutsu. As of now, A appears to be physically stronger, but we don't know who has a better stamina. The Daytime Tiger would be the greatest threat to A, but looking at how Jugo's blast didn't affect A, maybe he would dodge it too. I believe A has more stamina and would say A.