XD well he is pretty strong, strong enough to almost destroy the world. But the thing is that in Crisis Core Sephiroth takes on both Genesis and Angeal with ease, totally destroying the landscape and pretty much wins the fight, but in Advent Children its like he is barely even trying and just stands there and lets Cloud kill him without even blocking or countering. Crisis Core Sephiroth > Advent Children Sephiroth. Either which way they are both good fights, but IMO Advent Children was the weak point of the FF7 series.
Well have to disagree with you, Advent Children was the STRONG point of FF VII. In my point of view, Crisis Core was more of a weaker point.
So yeah, he almost defeat Angeal and Genesis, but they also have been defeated, and don't forget that after the Nibelheim accident Cloud was quite powered up by the Mako. So it's not that Sephiroth got weaker, just Cloud got stronger, simple as that. He got upper hand, but in the end he lost.
Sephiroth was much stronger in Crisis Core than he was in Advent Children. Especially when Sephiroth was "reconstructed" from Kadaj and S Cells, which in the end it was never truly Sephiroth that was resurrected, it was Kadaj acting as some sort of host which didn't last very long. Sephiroth used none of the powers he had like he had in the original, he used entirely blade attacks and Cloud managed to end it using Omnislash.
So I dunno, both fights are really good, but Sephiroth was much stronger before he died 8|
Everybody thinks that way, but in the reality he had full power in Advent Children. Kadaj was a remnant of Sephiroth. Yes, he wasn't as strong as Sephiroth, and he's body wasn't the same kind, but nevertheless when he put Jenova cells in him (not S-cell's, that was Jenova head he put inside of himself) he became Sephiroth, in all terms. He was able to summon that black sky, and it's not like he used in Crisis Core something else than blade attacks, so your argumentation is very off.
Oh, and Sephiroth didn't die in Crisis Core, he died when fighting Cloud in Northern Crater. Play the main game (Final Fantasy VII) before trying to prove something. It's the main game that matters the most.
As to the fight scenes, the one with Cloud is better, simply put it's more intense and the scenery and place where they are fighting is epic. It's not on a static place like cannon, it's between the falling pieces of Shinra building. That is epic and you can't deny it.
Don't sweat it. I've already helped many people so it won't make a difference to help another one. If I have a free time, and I'm not pissed than why shouldn't I help? I'm not a nazist german, or communist russian to think only about my interest.