IMHO, all these reports of "issues" with iPhone 6 or 6+ and even the new Air 2 are mostly non-issues.
If it's really a real problem Apple with definitely respond accordingly as they have done so in the past - ie the antenna problem with iPhone 4S (I think) and iPhone 5 (free replacement of battery for a particular batch), recent IOS 8.0.1.
Anyway, I am using iPhone 6+ 128 (for 3 weeks) and Air 2 (1 week). No problem with those reported "issues" so far for me.