I've chatted with people that love working on their macbook airs, and honestly, they have a lot going for them. They're nice light machines with a surprising amount of performance for their form factor.
I always argue that they're way slower than much cheaper machines, like a good workstation. Ergonomics aside, I wanted to get some performance numbers.
I've attached a script to this gist that will grab Sinatra and time how long it takes to bundle it, run the full tests, and run a single test.