I wonder how complex your design is. altium sure has more functions, but I don't now much about it because it's completely unaffordable for me. Even if it were affordable, I would not like to pay for it because of the atrocious way that company treats their customers.
And I agree that having to switch to another program does take time, but blindly choosing an expensive tool based solely on perception or reputation is also far from optimal. There should at least be some process to compare your needs with the capabilities of the software you are interested in. It would be a serious waste of money to buy altium, if it turns out that KiCad (or another lower cost tool) is adequate for your purposes.
Especially when you want to make an Open Source project, an Open Source tool Like KiCad has an extra advantage. And KiCad is quite capable. You can have a look at some projects made with KiCad on:
https://www.kicad.org/made-with-kicad/Alright I suppose that’s true but if I make an open source design with a cracked CAD the watermark is coming back to bite me.
As an intermediate solution, you can create a project in altium, and then import the schematic and PCB files made with altium into KiCad. KiCad has completely open and text based data formats, so there is no way to hide a watermark. An from what I remember from that "sued by altium" thread, altium "only" starts suing when it's being used for commercial projects.
I don't know your experience with EDA programs, or the complexity of PCB's you want to make, Therefore I also don't know if KiCad is be the right tool for you. Test driving a program is relatively easy. I made my first PCB in KiCad in the same afternoon that I started evaluating it. But then the "Getting started in KiCad" guide was excellent (but it was KiCad V3 or V4, a long time ago). Getting proficient and being able to use it quickly and efficiently takes a lot more time (maybe a month or so?) But that is not needed to get to know a program good enough for making a decision whether it suits your purposes. I think I tried 5 or more different EDA suites (and each for a day or so) before settling on KiCad.
For testing purposes, I recommend a schematic with about 10 to 20 symbols. A simpler schematic is not enough to get a real feel of a program, while a more complex schematic just takes more time to get though the whole design process. Starting with a known good schematic also helps. It skips the "design" step, so you can concentrate on how the software works. I advise to use the same schematic while testdriving different EDA suites, because this makes it fairer to compare those programs with each other.