Similarly, I switched away from Castro when it was melting down, and I tried out PocketCasts and Overcast.

PocketCasts is pretty great, but has one crucial flaw that makes it unbearable to me: at the time I was using it it was fairly slow to update feeds automatically, and you can't force an update of a specific feed. This got really annoying with subscriber-only feeds, because I'd know an episode had been released and had to wait a few hours for them to decide to actually let me see it.

Overcast is good at what it does (the audio boost features are the best of any client I've tried), but it's opinionated about a certain workflow in ways that don't play incredibly well with people who want to subscribe to a lot of podcasts and only listen to occasional episodes that catch their eye. Previous statements by Marco suggest that he likes Overcast's workflow and doesn't really want to adjust it to support inbox/queue users. In some ways the recent rewrite helped (the UI no longer locks up regularly when you have a lot of subscriptions), but in other ways it hurts (there's no way to give it a global episode-limit setting, and the default limit now actively wrecks playlists).

I'm inclined to say that if Overcast's workflow fits you, it's probably the best client to use. But if it doesn't, you have to make some choices...