Depends on your propensity for risk
If your tolerance for risk is high, dont take the exam.
If your tolerance for risk is low, immigrating to Canada is important for you and you dont want to take chances take the IELTS.
Without the IELTS it is at the discretion of the officer how many points he wants to give you.
I have spent a year in this forum and I have not come across a single case where the ppt took IELTS (> 7 points in each section) and did not receive an interview waiver.
