"Well it does work..."2.0 starson by Buzzwang
Pros: Easy connections, decent wireless range, simple design, same-as-always Cisco setup options we're all familiar with
Cons: Wireless-N speed is horrid for most adapters/computers
Summary: It works, it's stable and reliable. It's a Cisco product so generally I would expect that.Well, seems that the Dell 1505 WLAN Draft N adapter did the trick. 243Mbps at about 60ft through a couple walls and a china cabinet.
The problem is that, of 9 different wireless-n adapters I've tried (some single, some dual-band), on a Dell 1505 adapter ever connects at "true" N speed, that being 150mbps which is the max for the 1505 card.
I've run an Intel AGN4965 card, another Dell card (which is just a rebranded Intel I think) three different models of the Alfa high power USB adapters (single and dual-band), a D-Link dual-band USB, a Cnet (no relation I think) mini-n USB adapter (single band) and an Airlink dual-band USB adapter. All of these others connect at 56 or 72mbps ALWAYS. Only the Dell 1505 has ever achieved a real N speed of 150. Even my XBOX360 seems to be having speed issues with the E4200, and they were only 15 feet apart with no obstructions between them when I was doing my testing (opposite ends of the same room; no furniture between them, no walls or anything like that).
It's really rather disappointing that what should be considered a top of line Cisco access point/router would preform so poorly. By comparison, I've had most of these adapters on the same computer connected to other wireless-N access points and gotten full or nearly full speeds, so I know it's not some setting on the computer or for the adapters that is causing the slow down. I even switched the wireless to N-only on both 5 and 2.4 bands and still didn't get better speeds out of it.
I debated returning the E4200 and getting a Netgear or D-Link product instead, but decided that I should keep it as Cisco will most likely release a firmware update to correct the issue once enough people start complaining about the poor performance. Hopefully that will be sooner rather than later. Should it end up not happening, I've heard that the D-Link DAP-1522 wireless access point/bridge has worked well for many people, and they are getting high-speed wireless connections out of it using many of the same wireless adapters that I've already tried using on the E4200. I've been thinking about getting a DAP-1522 anyway to use as bridge in my new house (It's not going to be a simple thing to run ethernet cable in it after we final get the house).
Updated on Sep 15, 2011
So it's not my computer (i.e. windows or the software or whatever), and apparently the adapter of choice makes a difference. So 10 adapters later I finally found one that works, but that's a bit of a ridiculous effort to get a decent speed.