Meteor hit 1.0 b/c their APIs are stable. I'd also guess that the software has hit a level of maturity where the Meteor team is comfortable with a supported release.

As for Node, there are some within the Node community who would like to bump it to 1.0 as it is clearly production ready. In Node's case, .1 vs. 1. is a just a numbering scheme issue, not a production ready issue.