I 2nd that.. .OUTSTANDING reception, better than any other device in my home and I see 9 other wireless networks in my neighborhood (other machines/devices see 3 or 4 at most)!
Apple has put some outstanding antennas in the iMac. This card looks just like the Intel A/G/N (4965 I think) card I had in my Inspiron E1705.
I spent last night in a local hotel and had my new IMac with me. I was very impressed as to the quality of the connection using wireless. I did not notice any difference in performance from using my cable modem at home.
I have the new Imac, I would like to get access to the airport card so I can connect an external antenna. I have seen posts of the new Imac being disassembled but can not identify the wireless card. Does anyone know where it resides?