Oh man, I love OBS-Studio.
It's like a TV-Studio in a program.
To me it's like the modern day very-large-scale-integration reincarnation of the Video-Toaster. Video-Toaster came out in the mid to late 1980's by a little company called NewTek. It was an expansion board for the Commodore Amiga, and for the first time a PC could gen-lock with a TV signal and do real-time compositing of graphics and video-switching. Today NewTek makes the Tri-Caster which is like over $10k, but it's essentially broadcasting in a box.

Ardour is amazing, and Harrison Mixbus is too if you haven't tried it. Shares the same base as Ardour, but adds some other cool things. Price isn't bad at $89.
I do more "producing" than recording so I tend to like LMMS because I came from FL-Studio. Bitwig is also amazing, but pricey.