Question about podcasts usefulness

Asked similar question on another thread but here it may be a more appropriate place.
Personally I strongly believe in listening -- seen many cases when people visibly improved their listening and speaking skills.
A friend of mine yesterday argued that intensive listening to podcasts in foreighn languages it too difficult to be heplful (especially if you don't have a transcript before your eyes).
What are your thoughts/experience? Did you listen to podcasts? Did it help you?
Will appreciate your comments.