It's very very fast, highly customizable (plugins are easy to wrote) and it supports multiple database (I was interested in mysql, postgres & elasticsearch)

Small size ( it's really small!), single file. All functions, needed to me. It's great, that i should not setup any soft on server, configure web server (apache. nginx, etc ). If you don't have any right for doing this things - adminer helps. Simple interface - it's great.

It's as easy to setup and get running as it could possibly be - upload a single PHP file to the server, enter the Database credentials, get going!