Do you use an iPhone or Android OS phone?
I have an Android, but I used to have an iPhone. It's the only smartphone or product I've owned from Apple.
Which one do you prefer?
I switched to Android because they are cheaper to maintain, but I equally liked both. There are certain features iPhone has that Android doesn't, and vice versa.
Yes, iPhone's are pricey. I like the picture quilty of my iPhone 6.
I heard the iPhone 6 has a great camera, faster processor and improved LTE connectivity. Sounds like a great product.
Yes, so far so good. I had trouble with iPhone 3, 4 & 5.  Seems the iphone 6 has ironed out some of the bugs.
Apple seems to be a great company when it comes to upgrading products. All of their hardware including the iPhone, iPad, MAC pc , etc are all very functional.