I agree GB is fine, especially if you like it. It's where I started. GarageBand recently underwent a major UI change, and I hated the change. And I never really liked Audacity but it's perfectly good software too.
I'll tell you what I do like though. TwistedWave. I downloaded a trial, used it for a portion of the 30 day period and bought it. It's so simple and quick for recording single-track content like voiceover. Been using it for a couple years now and I cannot recommend it highly enough. I'm so efficient cranking out VO work through TwistedWave it's just silly.
Because I already had a copy of Final Cut Pro, believe it or not that's what I use for my multitrack projects, which are never that complicated. Voice, music, maybe a sound effect or two.
I used to edit my shows via an app called TwistedWave. It was enough to do some cutting and adding music and stuff, but I'd always end up moving it back to PC to polish it up before posting. Might be worth checking out.
My co-host has been struggling to launch a new show from his iPad though. I don't think you can really upload to Libsyn or anything from an iPad.