Specific wifi router type? for rMBP? I've recently gotten my cable internet upgraded. When the tech was here, he was able to get about 48 Mbps speeds over wifi, but on my retina MBP, connecting to the same wireless router, I was only getting 30-35.

We tried a number of different configurations, various wifi channels, and turning off the bluetooth on my machine.

How can i diagnose wireless prrformance to learn if a particular router type may work better with my Mac?
You shouldn't need to disable bluetooth on any recent Apple product - their antennas and drivers are very well engineered, and if you can demonstrate a slow down, you could get it repaired (most likely under warranty) since that's not normal. It is good troubleshooting - especially if your router is on 2.4 GHz.

First off, there may not be a problem. If you hold down the option key when you select the Wireless icon in the menu bar - take note of the transmit rate, MCS and other data.


What PHY mode is your radio? 
What band is your router? 
What MCS is being employed between the Mac and the base station?


Secondly, you can run the tests with the Wi-Fi Diagnostic that sits in /System/Library/CoreServices to check on the logs, check signal to noise ratio and much more.

If you are regularly transferring large amounts of data, you might need the higher MCS data rates - but it's rare to find a modern router (AirPort, Cisco/Linksys, etc…) that doesn't work very well with Macs. Usually it's an interference issue with spectrum and not that the hardware isn't properly matched. It's hard to tell without doing the work several days in a row to collect network conditions and graphs - but hopefully this helps you decide if/when to get a new router if that's the solution you choose.