I'm not sure where to start or what to write actually as I don't really have much information about this matter. I, myself, was once in a dilemma. Probably I still am because we have a project whereby we need to update monthly about the courses and universities that we wish to go to after A-Level.
As I have mentioned in the previous post, I'm taking 4 subjects excluding thinking skills. The 4 subjects comprise of Mathematics, Physics, Chemistry and Biology. To be honest, all 4 subjects are quite hard. It is one step further than the ones we have learnt in SPM. If I'm not mistaken, most of the subjects have 4-5 papers that we need to sit for during this 1 1/2 year period. All the science subjects have a practical paper whereby you need to conduct the experiments in the lab.
If you go in for March intake, you have to finish the AS syllabus by June/July, which means you have only 4 months compared to the January intake who has 7 months to complete before the AS trials. So you really need to focus in class so that you don't get left behind. And there are students who didn't get A for their Science subjects in SPM but still take all the Science subjects in A-Level. My advice is if you really can't do Sciences, don't bother taking them. But you can try. You can drop the subjects later if you decide not to continue with the subjects.
In Taylor's, there are 3 classes (March intake) for Pre-Medic program. While my class takes 4 subjects that I have mentioned above, other classes take different subject for their 4th subject. You can take Further Mathematics, Accounts etc as the 4th subject. What subject to take depends on the University that you want to further your study in. The compulsory subject for Medicine is Chemistry and I think they want Mathematics too. Biology and Physics are not compulsory. However, you should check the entry requirements for each university as they differ from one another. (Compulsory subjects for dentistry are Chemistry and Biology - University of Manchester)
So which is better ; ADP, SAM or A-Level? I'd say it depends on which country you want to go to. If you haven't decide, you should do A-Level then because most universities in the world accept A-Level. It is basically like SPM as it is exam oriented. You have two major exams, one in June (A2) and the other in November (AS). There's one year A-Level, but in Taylor's, they have 1 1/2 year and 2 year program.
As for SAM, it is 70% coursework (assignments, quizzes, presentation etc) and 30% external examination. It is only a one year program in which the final examination is in November. You need to take 5-6 subjects. Most SAM students go to Australia and New Zealand to further their studies. However, certain universities in UK and other countries (not all) also accept SAM. Which university? That I'm not very sure, so you need to do your own research. My friend said that they have lots of assignments and presentations to do.
In Taylor's, they have ADTP which stands for American Degree Transfer Program. If I'm not mistaken, it is a two year program and you're doing a credit transfer to a US university. So you'll study in US for about two years. It is more coursework-based. You also need to sit for SAT. Other than that, I'm not sure what else to write because none of my friends are doing ADTP.
Before you decide on which program to take, do more research on the universities that you wish to study in. And once you enroll into the program, just do your best! :)