(This email isn't to say that we're not investing in performance -- we know that there's a regression when rendering lists of new items and have solid ideas on how to address that)
Ok, so React and Ember (with their new HTMLBars engine) are competing with each other on this benchmark suite with 200 moving circles:
http://jsfiddle.net/Ut2X6/
Blaze performs more poorly than both on the same suite (by an order of 2 or so). But the truth is that this benchmark isn't very realistic -- most user actions do *not* cause every element on the page to be updated. Moreover, that benchmark is skewed towards React since React diffs the virtual DOM so it doesn't get that much faster if you only update one element.
The numbers that I get are:
- Raw (direct DOM manipulation): 0.12ms per loop
- Ember (with HTMLBars): 1.10ms per loop
- React: 3.16ms per loop
- Blaze: 0.52ms per loop
This is exciting!