The P'9521 is undoubtedly a striking phone. With its glossy mineral glass cover and brushed metal skin, it is instantly distinguishable from other clamshells.

As befits an established design house, Porsche Design did not choose to integrate cues from Porsche sports car design into their phones but adopted a futuristic yet minimalist design theme, consistent with its other products.

The phone is made rather thick and heavy for a clamshell, but these traits are a forgiveable trade-off, considering the company's innovative use of materials in the design of the phone.

The phone's casing is milled out of a solid aluminum block. The use of aluminum gives a unique sensation of quality to the phone – the hinges turn with satisfying mechanical resistance and the brushed aluminum has a texture that delights the fingers. The mineral glass used on the cover is simply gorgeous and possesses a sheen that plastic simply cannot replicate.

The only letdown in the phone's construction is the battery cover, which is a simple piece of rubber-coated plastic. For a phone that exhibits excellent build quality everywhere else, the design of the battery cover is somewhat incongruous and puzzling.