I can't advise on the podcast app - except to say that there have been complaints about it. You could try asking in the iPhone forum. I'm assuming there are no problems with your feed, but as you haven't posted its URL I obviously can't check it.
As to Libsyn, you need to ask them about your queries.
I am with Libsyn.
Per your questions - Yes - libsyn is worth it - Ok I am biased.
Yes - there is a limit on how much you can upload in any 30 day window - which is based on the level of account you sign up for. Here is an explanation of our storage - which is a growing / expanding storage - so no need to ever take down any episodes.
Yes - it is very easy to get your podcast in iTunes - our system is 100% iTunes complaint and we have more podcasts in iTunes than anyone else. And yes your episodes will all play fine. See the Nerdist, *** with Marc Maron, Today in iOS and Mac OS Ken for some examples of podcasts in iTunes using libsyn.
Please let me know if you have any other questions.
rob at libsyn dot com
Posted this on the other post, but this seems more recent
Joar - Have you managed to find a solution to this, i am having the exact same issue with my podcast
When searching for the podcast in itunes or on the app is displays everything correctly, but in the app as soon as i subscribe and view the episodes in library the epsiode titles are all the same.
After roger mentioning the Media Title tag in the feed, i checked mine and this is the same for me, it appears that it is looking at this tag to get the episode title.
Extract from feed
the 'tpsuk' is what all my epiosdes are being called.
So was wondering if you found a solution or where to change this in wordpress or the feed?
Any help would be great