While being partially open source, Symless charges for builds of their binaries, which is allowed by the GPL (open source license). Cost of $29 for Synergy Basic, or $39 for Synergy Pro. Older versions of the binaries are available for free, and the source code for the core of the app can be downloaded and compiled manually.
mhm, my experience is those that don't offer a free trial period for their consumer software know that it does not operate smoothly for many people = avoid at all costs
Still waiting for a free trial, seriously, expecting people to pay before even being able to determine if it is going to work ok on their systems, very bad service & mindset, seems I will put up with mwb for a while yet, I'd be quite happy to pay for the pro version if I first knew it performed better than mwb, which wouldn't be hard.
You can download the free and open source GPL
Synergy Core here on GitHub: https://github.com/symless/synergy-core
Do you have a free version yet, or at least a timed trial. I need to test whether it support two screens running an RDS session and the other two a normal PC. I have tried ShareMouse, it allows the mouse to move out of the RDS session, but the keyboard doesn't work. I need to minimize my session then the keyb works.
If you flip this around it could be listed as a pro. this is a paid (but still libre) software that allows you to build it for free (gratis). A lot of open source software doesn't even provide binaries for every minor or hotfix release. Software isn't free to develop and support, and although the open source community is better about donating to good software, the mainstream community isn't. IMO selling binaries is an amazing way to support open source software popular in mainstream communities.
Of course, this can also be looked as a pro as well. Feel free to add it as a pro if you wish :)
or you can just get the source code builds that are only a point release or two behind posted up on sourceforge.