If you're simply working with audio files, then I'd say Audacity is a really good option. A full-fledged DAW is useful if you're working with external plugins and MIDI files. But for basic audio work, Audacity will do well enough.
It's also one of the best supported and mature audio programs around, so stability won't be an issue at all
That's where I'm going towards next. I'm going to create a song from scratch using just Ardour and Zyn synth. I actually find Ardour's CPU usage to be more efficient than Ableton or Logic. And honestly, the learning curve isn't any steeper
Hi, author here. I aimed this list at non-technical people who wanted to make music for free. I avoided things like PureData and Sonic-Pi for this reason. Though if I'm honest, the learning curve for something like Sonic Pi isn't necessarily steeper than that for Ardour :)
It's also one of the best supported and mature audio programs around, so stability won't be an issue at all