It comes up because Meteor gets slow faster then most other solutions will get slow. It kind of reminds me in Django how a common mis-step for beginners is using an O(n^2) algorithm on the Django ORM. Meteor is the same way if you aren't using proper indices, or are trying do something that SEEMS doable to the uninitiated (like say pushing ~n thousand JSON objects into a MongoDB set), it's going to give you a bad time.