My first introduction to .NET was in the early alpha days, back in the early 2000s. In nearly the two decades that have passed since, it has matured into a very powerful platform. .NET as a platform has always had a great deal of polish that I haven't been able to find anywhere else. The ease of use and general technical excellence of the platform meant that I was delivering value at a consistent rate and with relatively little trouble.
That didn't make anything perfect, of course. The closed nature and the single platform that .NET was traditionally limited to took their toll. In particular, a bug fix that you found and reported might be fixed in the next release (18 months away) or not, with very little input or ability to understand what was going on.
And then the CoreCLR came along. In 2015, we made the decision to move the all of our applications and code into the CoreCLR.
That has been an amazing experience. The fact that I can dive into the source directly has made things so much simpler, and the fact that you can submit patches and interact directly with the core team has been an absolute joy. Our company has contributed several times (some code and mostly some interesting bug reproductions and perf issues) and has been continuously at awe at the level of commitment and (I have no other word) grace that we get from the team.
The fact that we can now run .NET code (and our product) on Windows, Linux, Raspberry PI(!) and Mac has been a great boon to us. We recently deployed our software to a whole lot of industrial robots running custom ARM boards. That is something that would have just been unimaginable every as much as five years ago.
In pretty much respects, the overall community, the core team, the engineering quality and the fact that it brings the polish that I've gotten so used to in environments where you are generally left cobbling things all by yourself means that it is my platform of choice for projects big and small.