Greetings, I'm someone who is using Dart in production I can tell you that is promising and the community is growing.

The only problem I see is that Dart developers are focusing to much in the newer stuff w/o ironing the basics first, for example, the DateTime datatype can't parse this: "2013-08-03 12:00" but can parse this: "20130742", and to me is more important to work in those basics than all the fancy Canvas stuff or polymer.

We don't know the level of compromise Google has with Dart, I'm taking the risk cause I think is worth it.