I personally thing that anyone comparing to two front end Applications built with two different stack.Performance of any app depends upon various parameters and most importantly it depends upon the Project Requirement.
As far as my experience with building application,I will try to list some of these parameters.
a) Quality of the test/benchmark code : Writing any application/module/function but writing a test case for these are comparatively more tougher.
b) Application Type : The main stack is choose on the basis of application type ,whether is data driven, small application or SPAs .The choice of framework all depends upon on requirement of the product.
c) Server load and Server performance : whether the server is able to handle multiple request .it all depends upon optimizing the server to its best .
d) Quality of Internet Connection at end user and client Side
e) Memory usage by the client Browser and type of Browser used. Resource utilization (CPU/memory/network)
f)Dom Manipulation : DOM manipulation should be very less and it is not good for performance.
g)Garbage Collection by the Browser.
In a nutshell ,no library or framework is good or bad .All we need to learn its pros and cons and best way to exploit it to get our purpose done,be in Backbone, Angular ,Ember or React.