About free and open-source software...

Free and open-source software, like Unix-derived PC-BSD or Linux works well, and there's lots of programs for it, but it doesn't integrate worth a damn with a system on which you're dual or triple-booting with one or more Windows systems, because the boot loader for the open-source system isn't designed to work well with a Windows Master Boot Record and its Boot Sector. If you aren't careful during the install, your open-source Grub boot loader will take over the whole thing, and then you can't boot your Windows on the same drive. You have to go into the Bios and set it to boot from disc, and then use a Windows install disc to do a repair of the boot sector.

And when you are dual or triple booting with the two kinds of systems, the Windows systems can't 'see' or read the Unix-based ones, because they use entirely different formatting for their partition on the drive. There are special programs meant to allow the programs from one system to work on the other, but quite frankly, they don't work worth a shit. And if you're in PC-BSD for example, you can't read Windows partitions, again because of the formatting. So, unlike two Windows systems on a drive, you can't exchange files or folders between them. It's like the other isn't there. To access files on the other, you have to reboot into it, and email yourself the file you want, and then reboot into the other system to read that email and use the file in it. Convenient, it isn't.

So don't rush into something you may have reason to regret later. However, if you install a system like the Unix-derived PC-BSD on a computer on its own, it will work very nicely, and there are enough free programs to allow you to do everything on it that you would usually want to do on a Windows-based system, and you won't feel particularly deprived while doing so. You can use popular browsers, and a free and complete office suite (LibreOffice) derived from the original OpenOffice begun by Sun Microsystems, and it will integrate with features from Microsoft's Office, such as files from Word, etc.