I have absolutely no experience here, but I have often wondered that myself. This article from Mashable reviews 12 screen casters.
I’m surprised that in that list Camtasia is not listed anywhere. It is pretty easy to use and not expensive. Although it is limited and not as rich as Adobe Captivate, I would say that it is more than enough for the big majority of videos (tutorials or not) that people do.
From that list I’ve only tried CamStudio and Adobe Captivate.
It is obvious that Adobe Captivate is the most complete of the two, of course. It is probably the most complete software of this type in the market (I’m not sure about this) but you do pay the price. And althoug I haven’t used the latest version (I think is 6), the highlight system didn’t make me very happy (simply, I didn’t like the aesthetics. You could personalize it a bit but still…)
where is Camtasia? I use that all the time. It was worth it and keeps on doing what I need it to do. Not overly expensive like others or the Adobe CS5 suite.
I am checking the ones on the list