What is your most used IDE? Is it also your Favorite?

Arduino.  Yes, it's my favorite.  I may have been using it since it first came out.  Long time.  Jupyter Notebooks are new to me but I'm liking them.  I've also use ST Cube.

Ive been using the V1.xxx Arduino tool the longest, and the most for E14 projects.

I have the V2 Arduino IDE installed, but it takes away the Old Bootloader stuff. 

Right Now Im using VSCode the most for writing Python.   

Comprehensive list of IDEs!

I use VS Code the most, but mainly as a text editor.
I really like CLion for C/C++ coding.

PyCharm is really nice too.

The old Arduino 1.8.16 is probably the one IDE I've used the most. I've never quite warmed to their latest offering (v2.13). More recently (over say the past 5 years) I've finally got to grips with VSCode (Visual Studio Code) as it's the most versatile - it can be used for C/C++/Python/microPython/Java/Javascript/etc. 

It's worth noting that Zephyr RTOS does not have an IDE at all. In fact since switching over to Zephyr RTOS I have had no real need for MCUXpresso, MPLAB, CCS (Code Composer Studio), or Simplicity. I simply use VSCode.

I started with MPLAB, but I did not use it very frequently. Later, I shifted to Arduino and have been using it for many years, and I still use it today. Currently, I am slowly transitioning to Visual Studio Code.

Eclipse for me.  I often use soft processors in FPGA and Eclipse seems to be the default IDE for that.

I started using VS Code as well... and I am very impressed with it.

I voted for VS Code because it's the one I use the most, generally speaking (just like someone else already said; mostly as a text editor, and I do the build/programming from the command line or with a plugin/extension like PlatformIO). Having said that, VSCode is still a bit of an overcomplicated way to do embedded, when there's better supported options available. If my target is supported by the Arduino IDE for example, and I don't intend to do extreme low level coding, I'd pick Arduino over VSCode.

Eclipse and Keil are also options that have (at least last time I checked) better debugging capabilities than VSCode and/or Arduino (at least for MCUs), so if I anticipate that I'll be doing a lot of step-by-step debugging and I have the hardware to do debugging on my target, I'd go straight to Eclipse or Keil, whatever is supported by the platform.

Finally, I spent a lot of time using MPLAB when I was younger, but I slowly stopped doing after they turned it into a Netbeans-based constant-crashing memory-hungry IDE (i.e: MPLAB X) so I've not checked whatever MPLAB is today, and how it compares to the other options, but maybe I should, just to have a more informed, current opinion about it.

VSCode for me, and while it's not my preferred one globally (hello Delphi), but for embedded, it's definitely my go-to solution with PlatformIO plugins and support.

I even worked with ESP32 IDF and MSDK inside VSCode, I'm definitely very used to it and I must say that a provider that today would require me to install their own IDE would have to have very strong reasons to do so to convince me to use their closed environment.

Well, two years ago it still was MPLAB X and still a weirdly unstable environment.