I used Castro for 5 years and loved it. But when it had the ownership meltdown I switched back to iCatcher. It’s quirky, but easy to set up an Inbox and Downloaded queue which is the Castro USP. I haven’t missed Castro and can’t say the news entices me back.
Haven’t tried iCatcher myself. It has that utilitarian look that usually either means it’s a power user app that can be configured to behave exactly like you want, or it is a hobby project of a single person without UI/UX talent. Going by your comment it’s the former ;-)
I’m lucky Castro fits my workflow (or rather, my podcast workflow came to be by using Castro since forever), and as it looks pretty as well I have no reason to switch apps.