I'm currently in the Basic (4 year) stream, but I can answer some of your questions.
It is PBL-based. All nursing programs at Mac, whether undergraduate or graduate (e.g., Masters) are PBL-based.
You do get clinical placements. There are less placements than the Basic stream, but you have to remember that accelerated nursing is only 2 years. I believe you get 4 placements (don't quote me on that) and the Basic stream will have 6 placements.
I know that some people will choose the 4 year program over accelerated because they'd like the extra time and be taught the basics. Accelerated does "skip" some things and get down to the information that you need to know BUT that doesn't mean you won't be competent or a good nurse. The expectations for accelerated nursing are different because you are expected to already have a university degree and some background knowledge (whereas Basic stream students come straight out of high school).
If you have any questions, the admissions staff for Nursing is super friendly. You can even go by HSC and chat with them or shoot an email.
I hope this helps.