(Spoiler) First time watching the entire show...

Ehh, I really disliked the ending too. The main thing that bothered me is that N did not outsmart Kira. The only reason he was caught was that despite Kira asking X-Kira to examine his notebook nightly with a microscope, some random character is so good at forgery that X-Kira didn't even notice the difference when it was replaced. This is unbelievable to a degree and also unrelated to the mental battle between Kira and N, so it was a really disappointing way for Kira to fall. I feel that it would have been satisfying if N had outmaneuvered Kira in any way, but in the end, they both knew what the other was doing ... N just happened to have better people doing it. I loved the fact that Ryuuk was the one who actually killed Light, even though Ryuuk actually knew exactly how long he'd have to wait around for Light to die (shinigami eyes and all), so his justification for doing so wasn't really in character (he said there was no telling how long Light would stay alive in prison if he was caught).

And yes, plot holes. For example, Rem had two notebooks - hers, and the one she gave to Misa. When Rem died, Light took her notebook, meaning Light then had possession of 3 of them (counting Misa's). Then when Ryuuk's deathnote was taken back, somehow Ryuuk was able to stay around despite the fact that both of their notebooks were actually Rem's. This might be explained by the trade-around they did before he lost his memory, but only one notebook would be tied to Ryuuk either way - which is apparently X-Kira's notebook, since X-Kira was able to see Ryuuk after that (at least once). So how, then, did the police force not notice that the notebook they have does not contain any of the names that it had when they first got it?

There are others, such as the death note rule that the notebook's borrower is unable to make the trade for shinigami eyes, and that the borrower is not followed by the shinigami, implying X-Kira fully owned the notebook and it was Ryuuk's. There's also a specific rule that if someone owns multiple deathnotes and loses posession of one, they can no longer see the shinigami tied to it, so Light should not have been able to see Ryuuk. This whole idea is ruined if somewhere off-screen Light gave Ryuuk both notebooks and then received them back, but that seems like an important detail to leave out. Also it bothered me when Misa was able to see Ryuuk though there was never a point where Light had her touch his notebook. These things are probably addressed in the manga but that doesn't mean the show doesn't have holes because they left out some details.

Anyway, with all that said, it was still really entertaining. The method of Kira's downfall was pretty bad, but the actual last few minutes of his attempted escape were amazing, and the confrontation at the end was nice. I just hate the way N 'won' without actually doing anything better than Kira; Light knew that N would try to replace the actual notebook and took precautions to prevent this. The only reason he failed was that N's people were far too talented, not because N was better.

/r/deathnote Thread