It must be a very boring life to purposefully work with uninteresting technologies. It may sound selfish, but I'd never make that decision. When I'm interested in what I'm working on, I build a better product. I'll sacrifice a few 9's any day to enjoy my job and make something that's interesting.
My excitement for the tools I use is directly proportional to the excitement I have for a product.
For example: over the past 4 years, I've all but abandoned all of my PHP projects in favor of my Rails projects. Because Rails is far more interesting to me than PHP. Just a small example, but it goes all the way down the chain.
I think it's probably a pretty sane life, to be honest. There's always some technology that's more interesting than what I'm currently using. The times I'm most productive are the times I haven't worried so much about that and worried more about how efficiently I'm spending my time.
We just made the switch at the end of last month, so I can't say anything useful. I do like their blog, which gives some insight into what it's like running a service like this.
The quote: "A rule of thumb that has worked well for me is that if I'm excited to play around with something, it probably doesn't belong in production." was what hit me.
That has to be incredibly difficult to adhere to, but doing so probably saves a ton of headaches.