Everyone's been taking a shot at the MacBook Air (ourselves included) ever since Apple revealed its features, but more importantly, its lacking features. One of those unimpressive aspects about the Air is of course the lack of a user-replaceable battery. Analysts believe that batteries may turn out to "Apple Achilles' heel" for the MacBook Air.

"Some users want more control over their notebook and there's no doubt that not having a user-replaceable battery will not appeal to those people," said Todd Rapparport, vice president of marketing for FreshBattery. The Irvine, Calif.-based company, sells replacement and spare notebook batteries online.

A company spokesman also claims that people are more likely to carry a power adapter rather than a spare battery, as many airlines are adding power outlets on their planes.

Roger Kay, an analyst with Endpoint 20echnologies Associates, also believes that the lack of a user-replaceable battery is likely to hurt sales of the MacBook Air: "A business user would find that completely unacceptable," Kay said. "Most of the people I know who travel a lot carry multiple batteries." However, he does see style-conscious consumers feeling no regrets for going with the Air, describing it as "a great design statement. It's very elegant," he said.

Mark Fleig, director of marketing for Batteries.com, goes as far as claiming that Apple's intent with the MacBook Air battery might have been to just keep all the revenue generated by selling replacement units.

But not only is the Air's battery stuck inside with no way of getting out except by unorthodox means, it is also a real pain in the butt for lasting too little time, should a user listen to music while also doing a bit of work.

The money.cnn.com article also questions the quality of Lithium-Ion batteries. According to Rapparport, they generally last 1.5 to three years before they should be replaced, and that's if you use them wisely. At 300 to 500 charge-discharge cycles, ever-savvier notebook owners understand that batteries are "the Achilles' heel of mobile computing and are looking for longer battery life," reads the report.

FreshBattery has these UberPower batteries that pack higher-capacity cells into the same size as the batteries they replace, offering about 75% longer run times. The batteries are 10 to 20 percent pricier than regular batteries.