i'd say sign up or not depending on what kind of tutition you are looking for....
all i can say about prior is that it is a coaching centre. Every week you have lessons and workshops to complete corrections to the homework they give you till there is no mistakes left. It is extremely time consuming. I'm in year 11 and i'm there 9 hours a week. Its been pretty bad..i'm on the brink of losing it and it especially sucks when you have an assessment due the next day or something, so i reckon for yr 12, if you choose to do prior you gotta be committed, which most people are due the the money they are spending
Prior gives you plently of notes and summaries, and examne you lots, it is highly advanced, at first when i started out my confidence shattered a little coz everyone there were really smart. It is because these people are all committed to getting the highest UAI possible, so really everyone there is creme of the crop. The prior system works to push you to a highly advanced level. I found that for maths, we were going too quickly, learning stuff i hadn't learned at school and kinda sucking at it, and i felt the system didn't work for me, i was considering one-on-one tutition because its a better option if you are strugglign to understand the basics. However i stayed with it for a little while and its getting better, u get used to it and i just ask lotsa and lots of questions!!!!
so if you need tutition because you are struggling, and need to understand the basics because u dont get it at school then get one-on-one however, if you wanna go the extra mile, and be more advanced than everyone else...go to prior, because the key of their sucess is they make you work heaps and push you to a high level....which not to mention, you can do yourself when you have the motivation!
good luck with ur decision
peace out!