I only upgraded because of the deal Verizon had. If not for that, I would have waited for next year. Having used it for a couple of days now, I can't really tell any speed difference with launching apps or opening websites. TouchID, is crazy fast, and some of the features that started with the 6S are nice (Raise to Wake, 3D touch) but not must haves.
My big gripe right now is using the lightning earpods and trying to two-handed type. Now that the headphones are plugged into the center instead of the side, I can't get a good grip. On the 6, I could firmly hold it with my right hand and comfortably type two-handed. Not the case anymore, and I've never been very productive typing in landscape. I plan on getting the wireless earpods once they launch so my issue should be short-lived.
The battery seems slightly better, but not a huge leap. The 6 was a damn good phone, this a mostly minor upgrade to me so far. I'm happy with it, but could have definitely been fine without the upgrade.