It all depends on what you want to do... If all you want to do is very simple clipping (clearing the genital area and anal region for example), or very straighforward jobs, the simpler clippers are probably sufficient. I have little experience with the Oster clippers. I've used the A5 with success, but I'm more comfortable with the Andis brand. I have a single-speed clipper, which does a very good job with most things, but for very heavy coats and heavy mats, my 2-speed clipper is better. It would help if you could tell me what you want to do... different jobs need different clippers!