I have been using Haxe (not professionally, but still quite intensively) for more than 3 years now. I've moved to it from AS3.0 / Flash initially to make games. As I learnt the language more and more, however, I started using it for a very wide variety of projects - data scraping / mining / processing, websites, image processing, scripts, etc. It has a small but quite active community and it is really easy to get in touch with one of the core devs, suggest features, or even contribute to the project.

If I had to point out its biggest flaw, it would be a lack of in-depth documentation - the API reference is understandable, the manual explains the language features quite well, but if you want to do some more specific things with a less-used platform, for example, you might have to experiment a little bit. I think this is a consequence of having a smaller community for a project which targets such a large number of targets simultaneously. However, since you asked about games, Haxe is great for gamedev. There are multiple frameworks which allow you to develop cross-platform games very smoothly. There are many games popular on Steam that were written in Haxe: Papers, Please (NME); Evoland (OpenFL? not sure); Rymdkapsel (OpenFL); the upcoming Northgard (http://northgard.net/, using the new Hashlink target).

I am also playing around with writing a framework, though it's nowhere near completion. I've written many gamejam games in Haxe (http://www.thenet.sk/), with source code, if that interests you.

If you want to try something new – I recommend Haxe wholeheartedly, even if you decide not to use it, I think writing code in it is just fun.