Overcast has the syncing perfected, but it has a much worse web UI. Pocketcasts new web UI is much slower too, with more clicks, popup windows, and less information density. I use the web interface during work, when I dont have my phone and just to browse quicker so speed and functionality are important.
Castbox has a great search interface that can find the words inside the audio of any episode, which is absolutely great for discovery.
Also there should be a simple subscribe button with 2 options: subscribe from latest episode, or subscribe from the beginning. Pocketcasts has a very strange way of changing subscribing to episodes just from sorting them differently.