Q: What's the ideal position for ads on search results?
Your ad's position on the page is determined by your bid, the components of Quality Score (expected clickthrough rate, ad relevance, and landing page experience), and the expected impact of extensions and other ad formats.
Although it is best to be on the top of the search results, it is best to have the ads appear on the 7th or 8th position of the paid results (this is the positions shown on the right side of the search results). Reason for this is because most people that click on ads on the top few positions will not lead to conversion.
You can find more about it at: https://support.google.com/adwords/answer/1722087?hl=en