Absolutely LOVED the finale!! Wonderful cliffhanger with lots of story potential to expand upon yet vague enough that it can be reinterpreted as the series finale with everything wrapped up perfectly. It was clearly deliberate on the showmakers' part to make it so just in case Fox decides not to renew.
I'd first like to gloat that I had been right from the start regarding Weaver's true allegiance; not on Skynet's side but not quite on the Resistance's either. She's a wild card operating independently from the two major factions.
For those wondering why nobody knew John after the jump, I think it's obvious. He's jumped into the future and it is from this point that he becomes the leader of the Resistance. As they're now closer in age, it's now more likely that John and Allison have a close/romantic relationship (hence why Cameron took on her appearance in order to get close to John as seen in the flashback episode). It also explains why they never showed Future John in any of the flashbacks; so as not to spoil the fact that he's not as old as he should've been had he aged normally and not jump ahead.
As for why Cameron gave John Henry her chip; I think it was to serve as the incentive for John Connor to jump into the future. Had she not been taken, I doubt John would've followed Weaver. That said, it's a pity that her body didn't make it into the future as well.
Overall, I really liked the episode. It really tied up quite a number of the loose ends brought up in this season, such as the Kaliba Group's role in Judgment Day and why Derek was so unceremoniously killed off (can you imagine what would've happened if he had jumped into the future as well?). Plus, I liked how they brought in some of the past characters into the episode (Chola, the Latina chick from the first season, and the priest from the first episode of this season). Finally, I'll state the obvious; that Cameron's attack on the prison was a crowning moment of awesome. Lastly, did anyone feel a little twinge at the second last scene when we see Derek, Kyle and Allison (essentially his only family other than Sarah) in the future, knowing that they are all going to die for John?
And on a more humorous note; this jump does introduce a plot hole... In the flashbacks, we've seen Kyle carrying a photo of Sarah. If John's jumped into the future without even the clothes on his back, how did they get their hands on a photo of her?