Good choice, can't really go wrong with any of the top devices anyway.
Got a pair of iPhone 6 phones in the family now and have been messing around with one that hasn't been activated yet. Here are my impressions:
1. It's just like any other iPhone before it. Same OS, basically same features, and little additions here and there but it's basically the exact same phone everyone is familiar with.
2. Build quality is excellent. I'm very surprised at how slim and light the device is, especially compared to my s4. It is a very slippery device though and with how slim it is, hard to really maneuver in the hand, could just be me though.
3. Looking at the screen compared to my s4, it doesn't seem that much smaller to be honest.
4. The fingerprint scanner is something I wish that Android devices got right. It really is pretty quick and painless on the iPhone.
5.It doesn't feel like a real significant upgrade from the 4s (which these new iPhones are replacing in my family).
All that being said it's a solid device. The bigger screen is a welcomed change in my book, but is definitely feels alot different than iPhones of the past due to its size. Even with this bigger screen and pretty nice features, I still wouldn't switch though, iTunes is a royal pain in the butt to use and would miss the customization of Android.