There is always some risk when updating. Though, there are many ways to reduce this risk.
At this point I'd wait for the iOS 8.1 GM which I'd expect to be released soon.
8.0 is working well for me, so I figure why mess with success. I think the old saying goes, if it ain't broke why fix it. I'm in a holding pattern with 8.0 and I don't mind.
I'm still on 8.0 on the 6 Plus and I'm patiently waiting for 8.1. The only issue I have right now with either 8.0 or 8.0.2 is the stacks+backboardd issue (even after getting a replacement). I heard that 8.1 fixes this issue so I'm patiently waiting.
There is always some risk when updating. Though, there are many ways to reduce this risk.
At this point I'd wait for the iOS 8.1 public release which will be released on Thursday.
yeah 8.0 is pretty smooth for me. at least as smooth as iOS 7.1.2 jailbroken was on my iP5. I plan on staying where im at until 8.1, or even longer than that as long as there is nothing major in the updates.