First things first - the delivery was prompt and it was from AAA deals (had opted for in-a-day delivery). The phone is very sleek and thin - might need a case if you have slippery hands. The build quality is excellent. Below review is from my own experience of switching from Galaxy S3 to this iphone 6+.
The cons:
1. The phone is big - if you have small hands/prefer smaller phones in general, this is not for you (especially existing iphone users - consider iphone 6 maybe). Existing Galaxy/Note series/Nexus 6 fans however might find it easy enough to get used to but..
2. iOS
Being an Android user myself till now, I think the features offered by iOS are nowhere a match for Android.. Power users will have to get used iOS a little. And most features that are in built into Android/Cyanogen are offered by paid apps in case of iOS.
3. Data
Although this is related to point 2 (iOS) rather than the phone itself, found it that big a deal to mention it separately.. iOS gobbles up data like mad, incremental upgrades aren't as efficient as Android (OS updates) and even regular apps are way heavier.. For e.g. consider this, Google sheets, that's 30-40 MB on android, is more than 110 MB in iOS. Considering android has to support more resolutions and phone models than iphone, I think this is gross inefficiency..
The pros:
The advantages now:
1. Battery:
The phone lasts 1.5-2 days easily with both location and background app refresh (sync) on all the time. My phone still has 9% despite 8 hours of usage and 32 hours of standby (after plugged out of full charge yesterday morning). That's a good 40 hours of usage. On the other hand, I'm yet to hear about an android phone that lasts more than a day with Sync, Google now and location set to on - even the nexus 6 would barely last a few hours more than a day.. This is not an understatement - this is easily the best phone in terms of battery life today (To be fair, worthy competitors in android are Note 4, Oneplus One, Nexus 6 & Moto Turbo - all of them come close but not quite matching up to this)
2. Camera:
The camera is still 8 MP, but has digital and optical image stabilization. Shoots fast and quite good - functions so smoothly. Low light photography works great. The only better phone cameras out there (in Android) are Galaxy s6 and LG G4. And considering this is just 8 MP but still matches up with the best cameras out there, the file size difference is quite an advantage..
3. iOS:
Although it has its pains, iOS still has its advantages - the entire OS feels very smooth and lag free (can't stress this enough - even the best of the Android phones starts lagging after six months or so). Even other minor features - the passbook, Stocks, Apple health all of them have equivalent Android apps, but the tight integration with the core OS is much better here. Also - iTunes sync - a lot of people might hate it, but this is still the best software to sync playlists and songs. To give you an example, you can even set a track to play only between the start of minute 2 and 3 on your desktop, and the same will get synced on to your iphone/ipod (tried removing preludes in a song anyone?)
So yes, this phone has its advantages and disadvantages - but at the end of the day if you just want a smartphone to last long, shoot great photos and are ready to experiment with iOS a little, I think this is for you. Considering the best android phones are almost the same price (S6/S6 edge) and given that they run Touchwiz, this decision was a no-brainer after all :)