Getting acceptance was much easier than I expected. We used coffee-script a lot before which has a bit of an overlap with Ruby/Crystal, which helped.

We've since moved to using typescript on the front-end and crystal on the back end and both type systems have a lot of similarities. They both also help catch many more errors earlier which gives us a lot more confidence in our code and simplifies the scope of tests which are needed. You can get to a point with a javascript application when you feel you'll create a new bug just by looking at the wrong way.

Crystal as a languages feels really cool. It's very low on boiler plate, which makes it really easy to read and doesn't take a lot of explaining. It takes the best bits of Ruby, so has a easy to follow logic which allows you to understand how everything hangs together. There is also very easy to get hypnotised by the 3ms response times when you're running it locally.

I'd say the only down points at the moment is the size of the community. The lack of 3rd party libraries and inability to 'google for a solution' could be an issue. However crystal's community makes up for in energy what it lacks in size, the gitter room is very active - https://gitter.im/crystal-lang/crystal

Web dev is not the most complex of programming tasks and our team is small, so your mileage may vary, but so far so good.