I can't see myself upgrading to this.
I have a 4 and was looking forward to upgrading last year, but the 4s is just too similar.
This very modest screen size change comes at the expense of making it look worse.
LTE coverage is mediocre in my area.
Developers will still be optimizing for the single core A4 for at least another year, so I won't miss out on apps.
NFC will be nice, but that will take a while to roll out, I doubt that will be useful for another year.
So, I'm left waiting ANOTHER year to upgrade...or moving to something like an S3.
EDIT: I forgot...I have no use for Siri, I already have Dragon Search...and it's nice, but I find myself using it only to show off the feature, usually I just type the search in.
Also, the new connector would be a pain as I have docks I regularly use and now would need adapters.
Oh, and one more: my big complaint with the 4 is that it isn't as nice to hold as the 3GS was. The 4s and now this new long phone do nothing to improve that.