Prior to my S5, I was an Apple addict (still am, really). Mac, iPhone, iPad, Apple TV. All in all, I love the entire Apple ecosystem. I also loved my iPhone. Switching to the S5 was a tough choice because I'd be starting over from scratch with my phone......learning a new OS, learning the Google/Android ecosystem, buying apps I had previously paid for through iTunes, etc, etc. But I did grow tired of iPhones/iOS changing it's appearance, but not really changing its ability. Same sh*t, different wrapper as they say.
And while I LOVE my S5, the truth is that if iPhone 6/iOS 8 came with many of the same features (multi-tasking/split screen, > 8mp camera, widgets/customization options) then I'd jump back on iPhone in a heartbeat. Needless to say that after reading up on iPhone 6 and iOS8, I saw nothing that was truly innovative about it. And as others have mentioned, the "latest and greatest" improvements are things that Galaxy users have been able to do for quite some time now. It's cool though. I'm under contract with this phone for another year+. By that time, I'm sure there will be a new iPhone getting ready to hit the market. If it's on par with my S5 (or S6 or whatever Samsung has out there at that time), then I'll likely switch back to iPhone. If not, I'll gladly stick with Samsung.
I do know that I'll likely never own a droid phone from anyone other than Samsung. I've got 2 Samsung SmartTVs and I love being able to mirror my phone to the tv without any additional equipment (like an Apple TV). So it's either Samsung or Apple from here on out for me.