Well, don't know if you can have both, fast but powerful with plugins and widgets. The extra's can bog things down.
But... I think it depends on the person and what they want to do. Could be many different answers.
I want a CMS that does what I need when I need it. What that is depends on the project. Though Worpdress has been my choice for pretty much all my sites these days. It can do so much.
Though curious to hear from others, their experience with other platforms. What's the options these days? I know there are others, but how many are as flexible and extendable like WP? If that's what one needs. Plus a platform thats going to be around in the future.
Years back I started blogging with Moveable type. Was the best at the time, now it's pretty much history.