Like many others, I’m finding the 13 inch MacBook Air a very capable substitute for my 15 inch MacBook Pro.
The two main obstacles both relate to file storage. I’ve been running a dual Aperture Library strategy for a few years now. I have a project library on the internal hard drive and a large reference library on an external FW800 disk. There’s also the slower USB drives used for Vaults. The Air lacks FireWire, so I need to use USB 2.0 to access the big library. But it works well enough to transfer a project onto the internal SSD drive in the Air. It just takes some planning and time.
The other obstacle is saving Photoshop files on the Air. Its a lot slower than the MBP. This is presumably memory and processor dependent. SInce I work in bulk with Aperture it’s not a big workflow issue, just the only big noticeable step backward in moving from one system to the other. Filter and layer speed on the 2GB Air is perfectly fine.
It’s been suggested that the SSD helps the photo workflow because it provides fast virtual memory. This may be true. In the past I’ve always had Macs hang because of paging memory to disk, a situation improved by adding memory to the Mac. An SSD may be a more cost effective way of dealing with this compared to actual RAM