I started using Pelles C years ago, probably in 2010 or so, had my up and downs, stumbled across number of bugs over the years in the IDE as well. At first I was just an amateur programmer with C/C++ background and pretty good WinAPI knowledge. Over the years (in my professional career) I was coding mostly in C++, there was some Python projects and even recently Go.
These languages are OK, but if you look at the tools... well the path of current software development is to follow crazy people who don't care about memory usage and/or CPU instructions. That's insane when an ordinary text editor takes 500 MB of memory.
I just went back to C and Pelles C in my "hobby" projects. I was just tired of these super complicated inheritancy mess, virtual calls and so on. Overengineered code was my daily basis.
What I really think is that we (developers) should really take care of such projects like Pelles C. Nowadays there are no more (almost) hand crafted software like this. That is why I think this is an international treasure. There was a Watcom C in the past, I believe they did even a fork of it, but the development process is super slow there.
Yet look at Pelles C. We just received a brand new 12.0 release with modern C standard support. At the same time if you wish you can use an older release for Windows XP, Windows 2000 or even Windows 98 for your retro coding needs.
I really see the improvements in IDE and compiler itself over the years. I like the .chm documentation as well.
I love it!