It's a tough call.
Corporate customers will want a vendor they can call; or sue. Either motivation is typically a showstopper that will move them away from open source projects. Another advantage to commercial systems are the availability of near-turnkey solutions, e.g. S7-1200s, MicroLogix, etc. They know they will have to program the logic for the process, they don't want to have to load the operating system as well, or, more importantly, maintain the in-house skill to do so. In then end they "cannot afford free software."
But they also want broken, or poorly designed, tools fixed, which will typically happen more slowly, or not at all, with a proprietary vendor who decides what to fix on a profit-based metric e.g. see recent posts #14 and #15 here:
Meanwhile fixes typically happen more quickly on active open source projects, often within hours or even minutes of being brought to the project's attention. Because, although some are hobbies as noted earlier, it is reputation, often tied to ego, that is the motivator.
Also, an open source project can also bring tremendous and flexible resources to bear, such as individuals who have superior knowledge of specific domains but would only work on a given project for a few hours a year once the project is mature. Whereas a commercial concern has to do all work with the staff at hand, while paying for salaries and benefits, managing, HR, NDAs, etc.; it is not economical to get a specialist in to work short-term on a specific task.
This forum is akin to an open source project: I suspect the value of free advice regularly given away here would be enough to support an engineering firm that could easily bill at a very profitable rate on the open market.
Regarding version control, I consider Git/Github/Gitlab/etc. to have solved that adequately: the
automation of testing and code coverage via tools like Travis is a thing of beauty.
Another place where open source wins big is innovation. Have any of you worked with something like Docker? I just started and it is amazing, and there are many related tools as well.
Hardware costs are an interesting topic. Open source seems cheap, with a RaspberryPI a tenth or even a hundredth of even low-end commercial PLC units. However, once things like I/O and terminal strips are added, and more significantly the labor to organize and assemble it all, maybe the commercial units are not that expensive after all.
So there are many benefits to open source, but rarely are they enough to override the primary economic motivations first mentioned above; so I am saying roughly the same thing as ojz0r before me. I cannot speak to the specific projects referred to in the OP, but I suspect they will work in some situations. I have been impressed with AdvanceHMI, but then I am comfortable in a VB environment. I did my first project with it recently; I had to write only a handful of lines of code to implement the desired interface. That seems to be a working business model for open-source: give most of the product away; charge for a few add-one, but not much; presumably they make it up on volume. It's a bit of a niche, and now VB is going away.
This has been a bit of a ramble; thanks for reading.
Here's that link, but it's broken:
Click on it, and you will see summat like the image below; remove the "x" from the URL in the address bar (highlighted in red in that image; Firefox shown; YMMV) and hit Enter.
Or take the first hit here:
https://www.google.com/search?q=open+plc+project