Google AdWords' Ad Preview Tool and SERP

There is a lot of information online about this topic but I couldn?t find a useful pattern ? so the question still stands in my mind:
- Is Google AdWords' Ad Preview Tool an accurate method for overall SERP checking and determining the rank of your websites for different locations and keywords? (from a manual non automated point of view)

If you could share your opinions and expertise I'd be grateful.

Thank you

I am actually using it and found it to be accurate.