If you mean do they all pretty much have the same signal levels and such yes they are pretty much the same.
There are only a limited number of chips used for the radios mostly because it is a government regulated thing and few companies want to deal with the all the governments around the world.
About the only thing that is different is the antenna placement in the units, many times which is a trade off in the appearance of the unit compared to the performance.
It mostly does not matter since difference between people houses mean much more than the difference between the routers. In controlled lab conditions these reviews can show some differences. They tend to make it seem like a big deal but fail to explain why these differences may or may not be significant in a real world installation.
Since 802.11n has been around for a long time (at least tech wise) most major manufactures have optimized their equipment so there is little difference. Some of the unknown brand though may not be as good quality. The router I saw for $5 at the dollar store I have been tempted to buy just to see how bad it was.
I am looking through this list of the best wireless routers http://reviews.cnet.com/best-wireless-routers/
... and I am wondering if there is any real difference in the performance of the router itself, or, if the difference in price is a function of the ease of setup/configuration, "smart" features, etc.
So, what is it? Will all n routers perform the same?