I haven't been to a live seminar. I think the biggest gain from a live seminar is the motivation factor. Other people in the class keep you going and if you don't understand something during a class you tend to do one of 2 things. Ask for clarification or fake it and just keep going with the class to discover understand it later or have it clarified later.
Another gain from a live seminar is, you booked a date in your calendar to "do it". You are less likely to break that committment than with a home study course that you can do 'just about anytime'. Perhaps even leaving too much time between tapes and thus forgetting something that didn't seem important until the next tape. Or worse feeling that you have to start over because you left too much time between tapes.
Alex