This brings up an intresting point. Is someone a better Hero simply because they have more cultural? If that was the case we shouldn't be talking about either of these two.

Lugh the Sun God was the MOST culturaled out of any character in the ancient Irish myths. He was an Ildanach. Jack of all trades,master of all. When questioned by the doorkeeper to enter Tara, the doorkeeper said everyone who enters must have a vauled skill. Lugh was a carpenter,smith,champion,harper,poet,Magician,physician,cup-bearer,and a brass smith. Not to mention that he lead the Tuatha against the Formorians and won.

Maeve and Ailli held a very grand court at the hill of Cruichan. So much so that it was said to even surpass Emain in splender and grace. For Poets and musicians, That the high face of the king of Connaght shone brightest for knowledge and wealth. Ogma, a hero of the Tuatha De Danna invented the written word for Ireland.
These all have contributed something great to the cultural, but does that make them better Heros? In my opinion no. A Hero to me is someone,when the chips are down and you need to win this fight or all is lost,who do you choose? Top to bottom,backwards and forwards, every day of the week and twice on sundays, I say Cuchulain. He was time greatest of his time or any other. I'm not saying that he was a dim witted oaf who killed and did nothing more. In fact he was raised by the very best that Emain had to offer. To be a cultured Hero, to be raised like a king for he was the king of Hero's.
Finn was a great Hero during his time too, but arguments can be made the Diarmuid or even Oisin were better.