Ask: what is the best bot development framework these days? Microsoft, IBM?

Hi guys, At work we are exploring bot development. There are a lot of frameworks available and we have already tried out IBM Conversation, API.AI and Microsoft Bot. Each seem promising but its difficult to find a pro's/con's list.

What are your preferences and experiences?

A big criteria is that it should have good natural language understanding, ability to handle concepts/intents and ideally have some kind of UI which allows to set most things up. We will do Node.JS dev work for a custom API endpoints for bot to work with but would prefer not having to code everything.

Any insights are welcome!