OK... so I guess I will just post some summary of what my final decision was...
Over the past few weeks I have tried many code editors and even though I was looking for one that works on both Win and Linux and is free, I also tried others for which there was at least a free trial, just to see what is available.
Some I uninstalled after 10 minutes, others I used for several days and I think I finally found the one I was looking for.
I found that there are basically only two editors that could compete with the one I used up until now (Notepad++) - Sublime Text and Atom.
The former one is probably the most used code editor by programmers in general. It is very smart, thousands of plugins available etc. Atom is much newer. I think however that Atom is better. The reason most people use Sublime is also because it has been around for much longer and it is true that if you already are using Sublime, then Atom is not that different to make you change your mind, it always takes time to get used to a new editor. The advantages of Atom over Sublime are not so significant and one of the main disadvantages of Sublime is that it is not free. You can download a free trial and in theory use it as a trial as long as you want, but you will get a dialog popping up that you are using an unregistered version and it is expected you should register and pay for the program (currently I think 70 bucks). Therefore people already using Sublime most likely already have the license.
Why I think Atom is better than Sublime Text and why I chose it as my new editor from now on?
First of all, as I already mentioned, it is absolutely free and open-source. Next, it is cross-platform - you can use it on Windows, Linux and Mac. In comparison to Sublime it does look more modern and there are hundreds of themes to choose from. And if you know LESS you can even customize the themes yourself so you end up with exactly what you want (I modified one of the themes which now looks exactly how I wanted it).
Just like Sublime, there are hundreds of packages and add-ons and you will basically find absolutely everything you need - syntax highlighting, mini-map, color picker, bracket matching, FTP client etc etc.
Another huge advantage is that unlike Sublime, it already has the Package manager installed so you can immediately start looking for and installing new plugins. In Sublime, you first have to install the package manager, which for some can be little difficult.
Atom is developed by the developers of Git - meaning it is also allows you to connect it to your GitHub account and it has many features that allow you to completely manage your GitHub repositories directly from the editor.
Overall, it is free, looks very nice and modern, cross-platform and actively being developed and open-source (Sublime is not, so the plugin developers are limited to the API the developer released, which does not give full control over the software).
Any disadvantages? Well, probably the only disadvantage you will read about it is that it is tiny bit slower than Sublime Text. However... unless you are like me using 1GB RAM PC, you will definitely not notice that additional few ms and even on my PC when I tried Sublime and Atom side by side, the former took about 3.4s to load, the latter 4.2s (and remember that on a "normal" PC, like the one I have in my office with i5 processor, it loads in less than a second).
If you often do some coding I definitely recommend you check it out:
https://atom.io
