Nothing is good or bad. The difference is just of the mode you write your exam in and you should choose it according to your convenience. If you are bad at reading on screen and prefer reading hard copies, you should go for paper based test. However, if you have bad handwriting or are not able to write clearly, you should choose computer based test. In listening, you get 10 minutes extra for transferring your answers to an answer sheet in case of paper based test while in computer based test you will get 2 minutes extra just to cross check the answers you have already written. Speaking in both of the cases is either done face-to-face or via video conferencing.