You get what you pay for. You cannot compare the kind of computer Dell sells for $299 with the kind of computer Apple sells for $1299. When I need most mobility I got myself a $199 Asus Chromebook-like Windows box that now runs Ubuntu beautifully. It's cheap plastic, but I won't be terribly sad if it breaks.

Last time I bought a Mac, it was slightly cheaper than a similar Dell and much cheaper than a Thinkpad, which I'd have to reinstall and, possibly, deal with compatibility issues.

Is there a reason that you are not including the MacBook Air (not that it gets you that much closer to the $299 price-point).