Same here. As of now, only iOS devices (except for Apple TV) sync with eachother meaning, as you stated, that whenever a podcast on an iPhone is marked as "played" it will be marked so on an iPad or iPod touch. Even though the position isn't really working yet, syncing the "status" of a podcast is reliable.
When it comes to a Mac (or Windows, perhaps) and the local iTunes (which should be the master controller of all iCloud, shouldn't it?) this syncing is broken. It seems that Apple didn't include iTunes to the podcast-syncing via iCloud and messed it up with iOS6 and its removal of Podcasts section in Music-app.
So if you subscribe to a podcast on your iPhone, it'll certainly appear on your iPad but it won't on your Mac and vice-versa. If you subscribe to the same podcast on your Mac and your iPhone, they sometimes get synced (depending on whether you set syncing under "Podcasts" section to off or on), sometimes the status gets reset to unplayed and sometimes, it just doesn't do anything. Fix this, Apple.
In my setup:
- Podcast syncing set to off (since this option means, that podcasts will be synced manually every time I sync my iPhone, which rarely occurs)
- Downloading podcasts to my Mac, listen/watch them there
- Subscribed (manually) to the same podcasts on my iPhone
- Continue watching/listening to podcasts on the iPhone
-> not working; need to manually scroll to the position, I noted down from the computer.
This is not how it should be. All this new fancy iCloud should make syncing easier and manually hitting "synchronise" obsolete. While this works with Apps and Books, it doesn't with Podcasts. For one simple "reason". You can't play or view Apps and Books on your Mac/in iTunes so Apple more or less "forgot" to implement the syncing process besides of automatically downloading the content between device and iTunes.
BTW, setting Podcasts-syncing to "on" doesn't seem to solve the problem rather than making it worse. iTunes/Podcasts app get completely confused, sometimes loading ALL played and unplayed episodes to the phone, sometimes just doing nothing and sometimes reset some played episodes to unplayed and vice-versa. So better let it set to "off" and either watch/listen to your podcasts on your phone or Mac solely until Apple fixes this.
Bummer.