It's desktop only (no Android or iOS support) which makes me wonder: what percentage of overall podcast listening occurs on a desktop computer? Polls on this are all over the place, but I would guess maybe 10-15%? For me, podcast listening has always been an inherently mobile activity, and it would drive me nuts if I had podcatchers on multiple devices that were out of sync with each other.
Incidentally I had used JuiceReceiver for years until it stopped working (due to the SSL algos from 2005 finally giving in) and then wrote a replacement in C++/Qt with an online backend, just to track which episodes I listened to (and because it was fun, mostly).