What a lovely thread.
Consider the network cable, by the power cable, where it's been for the last 5 years in my apartment, sitting there, saying: well, you could, you know, have bought a laptop that has a port for me, and none of these problems would hit you when you're actually busy.
First order of business is an network cable adapter, maybe even the thunderbolt one from Apple.
So I have a 2013 Macbook Pro Rentina with 10.9.2, which has that 6.30.223.154.63 broadcom driver, and a (Cisco) Linksys EA3500 router with firmware 1.1.39.145204 (a 2012 vintage, a good year for selling subdivisions).
I am on the 5Ghz channel 36, mostly, and I am getting RSSI -52 at the 450 rate (which I'm guessing is mbits).
The two main problems I still see a dropped block of packets now and again which is just enough to disrupt my use of vpn... which otherwise I wouldn't notice. And yes I usually have bluetooth on, though I've seen it with it off too. And second, the annoying issue, is when waking up I am told I don't have a connection (in my browser) while the network claims to be connected to the right SSID. This either takes a good 5-8 minutes to resolve "itself" or I have to turn the airport off and on for the... hello everybody, we've all woken up and we're ready to go now, are you coming along built-in wifi? effect.
I don't plan to replace the router... I don't plan to walk around with a dongle... so this is how I make do, turning it off and on. I do plan to see when an update will actually address the issues. I can understand that perhaps it is the EA3500 at fault (though no other computing device I use has the same issues).
As an aside I'd like everyone to read up on why doing actual (albeit network) file operations is not a good way to test network speed, and familiarize themselves with some simple tools that'll make you feel better about it:
http://khmel.org/?p=228 [man nc, man dd, dev/null dev/zero]