This is likely true under certain circumstances (see the several other threads supporting better signal using G-only). I'm wondering if it's also that the iPad may work better in the 2.4GHz modes. Again, I think it will always depends on your specific setup, surroundings, etc., but I've had more success with G and 2.4GHz N with both an Airport Extreme and Belkin router.
I'm curious to hear what other users are experiencing when comparing the two. However, it's clear that Apple needs to address the N connectivity problems some of us have had. Hopefully this is one of the "other issues" they are referring to when they announced a future firmware update.
Edit: I should also note that my girl's MacBook has much better speeds in N so we keep the Airport running separate N and G bands to connect to. If I'm close to the base station N speeds are pretty good, but just one room over I have to be on G to stay connected. Regardless, her MacBook's signal is better than the ipad in any mode. I guess that's expected (more antennas, blah blah).