I just think it tied together everything so brilliantly.

If it had ended with the Gift, we wouldn't have gotten Seasons 6 & 7. Plus, I love how Chosen ended with the complete destruction of Sunnydale and a new beginning for the Scoobies.

I love both episodes and think they both would have made amazing finales (and while I think I would have had a complete mental breakdown [oppose to the semi-breakdown I had] if Buffy would have died and never been resurrected, The Gift would have been a wonderfully dramatic series finale).

But ultimately the biggest story line (and premise) of the show was that there was only one slayer and as a result Buffy "knew" she would die at a young age like all slayers do, she felt alone, and she really struggled with the burden of slayerhood. I think both The Gift and Chosen tied that story line together by resolving the dilemma, except it was done in 2 opposite ways.

In The Gift, Buffy comes to the realization that being a slayer is who a part of who she is and that "death is your gift" did not mean that she was a slaying/killing machine, but instead that her death would be a gift to the world. She is finally at peace with her calling, and the episode ends with Buffy facing the early death she always knew she would have and ending her burden of slayerhood.
In Chosen, Buffy also ends her burden of slayerhood- but in a completely opposite way. Rather than making peace with her calling by giving up her life & dying, she makes peace with her calling because she becomes one of thousands of slayers around the world.

In both cases the show would have ended with Buffy no longer being the chosen ONE (because she'd die or share the calling with many others) and with Buffy finally making peace with her calling as the slayer. But since we get to see this whole storyline resolved without Buffy dying in Chosen, I'm really glad Chosen was the series finale.

While The Gift would have been perfectly good as a series finale. Chosen tied everything up much better together. Plus if they'd chosen the former as a series finale, there would be no Once More with Feeling, Tabula Rasa, Conversations with Dead People, and other such episodes. Although it would have meant both Tara and Anya would have survived. And where would the "season 8" comic be, a season 6?

Perfect ending!