you're all on crack! 
This is neither an iPad-specific problem nor a wireless N-specific problem. It's related to 5 gHz vs. 2.4 gHz. I experience the same issue with my aluminum Macbook and Cisco WRT610N.
5gHz signals have less of an ability to go through walls than 2.4 gHz signals. The tradeoff is that you have more bandwidth available in the 5gHz band, as well as less interference from neighbors routers, Bluetooth, microwave ovens, etc.
In the same room, you will almost always get better performance with 5gHz. A few rooms away, you are almost always better-off at 2.4gHz.
I do get 300mbit/sec connections with my Macbook in the same room, BTW.
so Jtara is the first one who actually understands RF and how frequencies affect penetration. He is correct above but there's a lot more to it. Here is a collection of facts to help you guys out.
1. 802.11n is not 300mbps, its 150mbps. You can make it 300mbps if you fix your channel and utilize a 40mhz channel width instead of the usual default of 20mhz. Both your AP and NIC have to support and be configured for the 40mhz width.
2. 802.11n works on BOTH 2.4 and 5ghz (hence "dual band").
3. 802.11n has a full 2x the range of 802.11g. This is an incontrovertible fact of the technology.
4. I know all this from practical experience because my Cisco wireless plant has over 5,000 AP's on it in 250 buildings and I can see in the detailed heat maps the range, errors, and throughput for every AP and every user 802.11a/b/g/n (and triangulate their exact position) overlayed over the floorspace which also tells me the exact dB loss for every object in the room (chairs, cubicles, glass, water coolers, everything).
So in conclusion 802.11n is superior.
