D-Link DAP-1522 :: Wireless Connection Usually Much Slower Than Other AP

I have a defective DAP-1522, or what. First off, I have never been able to access the unit at http://DLINKAP when my computer is connected directly to the 1522 via ethernet, only 192.168.0.50 works to bring up the web interface.

Second, I have more than one AP at my house, but the DAP-1522 is the only networking device I have have problems with (I am using the unit in AP mode). Basically, the problem is the wireless connection usually is much slower than my other APs (both N and G), even when the computer is physically right next to the DAP-1522. And that's when the unit is at it's best. At it's worst, I can't connect to the internet at all, even though my laptop shows full signal strength. The 1522 just seems really finicky. The problem doesn't seem to be a networking issue, because a 2nd AP that is connected through the wired portion of the DAP-1522 works perfectly, implying the 1522 is having no networking issues when using the ethernet ports. But since the problems persist with full signal strength and with the computer right next to the 1522, it doesn't seem to be a wireless connection issue either. And I have no problems connecting to any other wireless APs I own (and I own about 5 others, not that I use them all at the same time).

If I could, I would return my 1522, but I've been tinkering with it for too long now to return it. It has caused me a ton of frustration. I had a wired-only router for a long time (hence the purchase of the 1522), but just bought a new wireless-N router that is performing perfectly (as a router, and as an N AP). I hoped the old router might have not been playing nice with the 1522, but have seen no improvement with the 1522 wired to the new router (on opposite ends of my home).

Note that I use Macs only, no Windows machines. I started with the 1.02 firmware for the 1522, now have 1.20 firmware, but have noticed no improvements with my issues.