I took ISI's Online Ethical Hacking course. I do want to say right up front, that from what I have been told, and have guessed, I would not jump right into the 10day course without previous experience. Specifically, you need to be comfortable with linux, scripting and programming.
Now that that is out of the way, I'm fairly certain I offered a review of the online EH course, feel free to look at my topic history, where you might find the link. I agree with awesec, it depends on your experience level, and perhaps more importantly, your time constraints and discipline. If you have the time and can force yourself to sit and listen to the presentations, read the book, then do the labs, it should only be mildly challenging, and certainly exhilarating. I however, would seriously consider taking the ground course, if I could.
Ultimately what has prevented me from taking their ground courses is the additional costs of transportation and lodging. Especially for a 10 day course, the hotel costs could kill you.