The 2011 MacBook Pros suffer form bad Airport performance with unstable ping and packet loss. The issue is not just affecting my computer but seems to be a general issue with the 2011 MacBook Pros. This has been confirmed by both the service center that tried to fix my computer and by Apple engineers. The service center tried to replace the Airport card and a fresh install of the OS but the issue persisted, they also tested one of their demo computers with the same result. Apple got logs from me and tried the same experiment on one of their 2011 MBPs. That computer is also affected by the same issue. The unstable response times are easy to see if you ping a computer on the same network. Response times vary between less then 1 ms up to and above 300 ms. Average seems to be around 100 ms on a network where other computes receive their response in less then 3 ms on average. I also notice near 100% packet loss from time to time. (Several times a day with heavy usage.) The 5 GHz networks seems to be worst affected by this, 2.4 GHz networks are slightly more stable in my experience. Apple has told me that the engineers are aware of the issue, that it affects all 2011 MBP (13, 15 and 17), but that there currently is no solution or timeline for a solution. They might fix it soon but on the the hand, there might not be a solution until Lion.