Which is better?

Both have their advantages and disadvantages. I will quickly summarise my opinion upon this based on what I know.

Firstly audio podcasts:

Audio podcasts are good because:

They don't use as much bandwidth

For information based content you can pack in a lot more information than in a video podcast of the same size

Where video does not add to the content in any useful way, this is recommended

Hosting your podcast is usually cheaper since bandwidth is not as great

Video podcasts are good because:

You can provide visual content to enhance the information message
Visual content, lends itself more easily to branding and also display of additional advertising in a visual form which may be more attractive to advertisers
If you want to get into tv, the movies or advertising you can get more exposure for yourself, especially if you appear in it by using a video podcast medium

Bear in mind with video, there are many formats and not all of them are compatible with every viewer. Consider the format of your video carefully before committing.

So as you can see the format you use is not cast in stone. You can use both as well. Such as Joe Satriani in his super colossus podcast. He has an audio and a video version.

Ultimately the form you use should be determined by a careful consideration of your goals, combined with an assessment of your marketplace.

Graeme Sprigge
www.podcastdir.net