Personally did it but I've got a friend who got 100 percentile without MedEntry or any form of preparation whatsoever. He didn't even want to get into Medicine and was just forced to by his Asian parents really. As for whether or not to, it depends how much you value getting into a health science. UMAT is quite a limiting test in terms of your potential to do well. Simply studying it a lot will not necessarily give you a good score. MedEntry will increase you to a bit above your current level, whatever that is. Let's say for examples sake, without MedEntry you would have got 85 percentile, and with it, you got 95 percentile. A score like that gives you access to basically any health science, and if you were wanting to do Medicine for example, then that would've been money well spent since you'd need at least a ~93 percentile for that. But for the majority of MedEntry users, I'd say it looks something more along the lines of jumping from a 60 percentile to like a 70, which is more or less a waste of money since both are equally useless scores. Problem is, it's quite difficult to determine where abouts you lie at the moment. So if being in a health science really matters to you, then yeh go for it. Otherwise just wing it and see how you go.