Are the O'Reilly / Useractive Courses Any Good?

IronBlade asks: "Hi all, I'm very interested to hear if the O'Reilly / Useractive Linux/UNIX System Administrator courses are any good. There are 4 units, and as they are offering them in a package (4 for the price of 3) until -Feb 15th-, I'm very interested in your opinion as to their worth. I have previous sysadmin experience on GNU/Linux and feel I have a reasonable grasp of things, but I don't have any proof of my skills, and certificates from the University of Illinois would be a Good Thing to add to the CV."