After having taken the GRE's in this format, I would NOT recommend it. The questions are aimed at the individual test taker's ability, based on the response to the prior question. It is easy to become frustrated because each question is intended to find the level at which you max out, and therefore all questions are difficult for the test taker. You must also answer all questions and you cannot go back to previous questions. The test-taking strategy of leaving blank and returning to difficult problems does not work.
Time is also a major concern in the computerized test.
Since you cannot return to a question, it is difficult to determine when to give up and guess on any given question. I would strongly urge students NOT to consider the computerized tests an option and to plan their test dates accordingly. The only compelling reason to take the test by computer is an application deadline. Until software is available which actually simulates the computerized testing, students will not be armed with adequate test-taking strategies for the CAT format.