Here is my ABC Logic. (It's actually a bad idea to HAVE ABC logic, because it usually depends on the writer, but i will utilize it anyway, because i often nerdrage about how underestimated Spider Man is)
I like Namor better than Aquaman, I think Namor is a better character than Aquaman, that being said Aquaman would beat Namor's ass
The following statment are based of comicvine stats and comicbooks.
Aquaman has a little more strength, is a better empath and has water magic, Namor however has double the agility and flight which will be a huge advantage because there in New york,
Namor is also better at hand to hand combat he has power over electricity which will help during this rain storm, He's also a better swordsman and weapon master. also even though Aqua- man is a little stronger Namor has a beserker strength which is a quick rush of strength for a few minutes. the Sub-mariner also has more stamina. now to make this hurt more Namor is also a little smarter then Aquaman.