kenny_devon:
Microcontrolers control real things that can be dangerous, in my case a kiln. The doubts are surfacing ... Is this a genuine development environment, or just a hobby playground? Is Arduino a trustworthy babysitter for my kiln?
The primary design focus, as far as I can see, has been educational. Hence the presence of the String class at all. And some of the other "simplifying" aspects to the IDE.
However like any other open source system, the bugs are being detected and cleaned up.
I am using an Arduino as the security system for my front door. So far (over many months) it has not failed in any way. I use others for other purposes, also without problems.
I would suggest for something like a kiln, whether it is an Arduino or some other device, you not have a single point of failure. So for example, a thermostat or something as a secondary backup. For mission critical things I would be thinking "what if the power fails?". OK, battery backup. What if the battery fails too? What if the wiring gets corroded?
I think once you move away from the String class, things will become more reliable. Also keep in mind things that might go wrong later. Eg. when millis() wraps around after 50 days. That can be handled, easily. But you need to be aware of it.