First is processing power. Google is now promising processing for up to 1 billion hits per month compared to the standard 10 million a month. The 1 billion is a cumulative total of any amount of sites, so you need not fear having to get a premium account for every one of your sites even if the cumulative total is less than 1 billion hits. This should also translate into having an all-around faster tool set!
Second is advanced analysis. You will have more advanced attribution modeling tools that will allow you to run different models to better assess the value of varying channels and their ability to drive traffic.
Third is a new level of service and support. Google will be providing experts and knowledge to resellers to help with installation. Google will also be providing 24/7 support for complex issues.
Fourth is a set of guarantees to the user. Google will be have service level agreements that will result in compensation if they do not meet the following guarantees of 99.9% data collection, 99% reporting uptime, and 98% data freshness.
So what does this mean? To the average sized website owner, not all too much. This really can be thought of as more of an enterprise level version of Google Analytics, but the ability to have it used as an umbrella tool for multiple sites makes its appeal wider to website owners of multiple sites. Regardless, worth knowing about and great to see Google continues to freshen up old, but popular products.