Got my 64 GB Plus yesterday... it crashes to the Apple logo and boot-loops constantly. Maybe the issue is something else? (It only happens if I restore from my old phone, but if I don't, of course, I don't have my stuff. It also only happened after the 8.1 update--not that I tested 8.0.2 for long.) It certainly seems similar. I'm guessing it's Springboard that is dying, although it's not the (pretty harmless) "quick Springboard relaunch" that I saw occasionally with earlier iOS versions.
I don't think I've ever used a x.0 OS from anyone, but in my individual case, this is the worst x.1 I can recall. I bet more than 50% of people are fine... maybe a lot more... but I'm stuck. Can't even use my phone as an alarm anymore because it crashes when you put it to sleep half the time. Conclusion: do NOT install iOS 8 yet. Wait (But I had no choice, with a new phone.)
I predict another "-gate" mass hysteria article, followed by people coming out of the woodwork saying that this has happened to them. Then, a class action lawsuit against Apple, when in reality it will probably only affect a very small percentage of users with iPhone 6 Plus 128GB models.
Here's an idea - if it seems to affect only those that have large app libraries, why not restore as a new phone? Use it a little more each day, and see if the issue persists. Then, you might be able to pinpoint it a little better than "OMG! Apple doesn't care about QA anymore!"
That's a terrific test step that people with large app libraries (games, in my case) could try, just for the experiment. But it's incredibly time-consuming, and you lose your app organization, your game progress, your files in non-iCloud apps, your settings and passwords in ALL apps, etc.
So no, it doesn't makes sense to insist that that QA situation (large libraries) should fall on the shoulders of users rather than Apple.