MacWorld UK warns in its blog that the 1.8" 4200 PATA drive may offer reason for real concern about speed. All the reviews I read from MacWorldSF fail to mention if they are on 1.6 80s or 1.8 SSDs. While the SSD costs a lot, the Air costs even more and to buy a machine that drags due to a crap hard drive would also be a disaster. The interface, disk size and speed each contribute to slow things down compared to what most of us are accustomed to. The question is how much will this drive impede user experience, and how much will the SSD enhance it.