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I use power support anti glare on my iphone 4 and its top notch. Therefore one could assume that the MBA version would be just as good. Plus the other site you suggested seems a bit low end.

The real question is if the anti-glare film would blur the screen resolution like it does on the iPhone 4. It was a fair trade off for the iPhone 4 for both anti smudge and anti glare feature, but on the MBA not sure if it would be worth the lose of resolution.
 
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