Known concerns I have with using a MacBook Air as a Windows 7 machine are:
- Blue Screen of Death caused by appletmp.sys, which may require a full re-install of Windows 7.
- External USB optical drive requirement
- Limited "Genius Bar" support
Potential concerns are:
- SSD "Trim command" support or lack thereof
- Ability of Windows 7 to use external 27" Cinema Display
These are more problematic.
Are there others?
Primary use will be photo-editing (Photoshop Elements), QuickBooks for Windows, Outlook, and presentations. The virtues of MacBook Air over other devices are battery life, SSD, build quality, screen quality, and ultra-portability.
I have installed Windows 7, but I have not yet discovered whether TRIM is surfaced in the BIOS.