Regardless, we stick to AWS at work for the entire suite.
When it comes to my money though, DO is making very large strides imo
Can you provide any more specific search criteria?
I've found Amazon instances to be quite consistent. They vary, of course, but quite contrary to your initial statement that they vary wildly, I find the variances quite small, and there isn't a need to constantly hunt for ripe instances. I have absolutely found what you said to be sadly true on quite a few other VM hosts.
tl;dr: Netflix kills slow performing AWS machines due to resource contention