I am considering a MBA, but wondering to hold off until october. When some have mentioned "poor performance" what exactly do you mean? Is there lag in program use or are you referring to the limited specs?
I can foresee an upgrade HD next month to the 120 GB's in the new ipods, and probably a speed bump up to 2.0 GHz.
That truly would be a miracle, as there is no 2.0 GHz chip in the line. The Macbook Air's current processor was a "one off" die shrink design. The next chips will be 45nm and will most likely be the 1.6GHz SL9300 and the 1.86GHz SL9400 processors which use less power and create less heat, thereby increasing battery life.
The heat decrease will make it easier to cool, which will help problems with core shutdowns that you can read about here in the forums.