The Bad- is in the realm of Pay per click, questions that arises are: will this feature hurt the marketers bid?, will it kill the long tail? Must we bid keyword partially like if I'm typing "carpet show" here is what is shown:

Why does Google show  carpet show case?,  but what I was looking for was carpet showroom & carpet prices in Bellevue.  The time that it takes to read the suggested keywords an impression is counted.  Is this information accurate enough to count in the analytics for your purpose?

In summary mine your analytics data carefully, and know all of your Key Performances Indicators and from which search engines that its coming in from. You can filter the traffic and take into the account of instant search and compare the new data with your historical data.