The flexibility and capability is top notch. Looker is really quick to innovate and add new features. We love that the entire of basis of Looker is about querying your database in real-time. With this, there's a lot of transparency into why a query isn't running or why results aren't as expected.
The support team is great about referring you to the right documentation (which can be hard to find), but they're not as great about coming up with creative solutions to unique problems. Oftentimes it will result in a mention to the product team. More visibility into the feature roadmap would go a long way.
It isn't the most intuitive of the BI tools, but if you have someone that can dedicate some part time energy towards maintaining and troubleshooting, then the capabilities are superior to most anything out there.
The main business goal of looker has been making data more accessible for the data team and business users. The obvious benefit has been less reliance on the senior data analysts.