One of the things that interested me about the Mac Book Air with the solid state drive was the hope that it might give better performance than a standard HDD and even better battery life.

According to this review from Ars Technica, the performance gains mixed:

[T]he summary is: the SSD does worse in sequential disk tests and writing in general, but spanks the HDD in random disk tests and reading from the disk.

From No spin: Ars reviews the MacBook Air with solid state drive
Referenced Wed Feb 06 2008 20:58:53 GMT-0700 (MST)

What does that translate into?

• Booting is no faster
• Exporting a Quicktime movie is slower
• Building software is faster
• Unzipping an archive is faster

Most applications won't seem much different. In short: don't spend the $1300 in hopes of getting increased performance. You won't see much.