It looks to me like Horizon and Meteor are solving problems in different scopes of the application stack. Horizon looks to be more like the Minimongo/DDP/Accou

It looks to me like Horizon and Meteor are solving problems in different scopes of the application stack. Horizon looks to be more like the Minimongo/DDP/Accounts parts of Meteor, and doesn't help with any more of the stack like Meteor does (eg: In Horizon its more up to you to wire it into Angular/React/etc). Meteor is more of a platform and Horizon is more of a real-time client DB and account framework. If I had to choose between the two, Horizon would be good for if you had a strong opinion/technical need for very specific coupling between UI and DB, and Meteor for when you don't or need to get something out very quickly (eg: this weeks internal CRUD app for a few dozen users).