I've manage to get a hold of several smart-phones earlier that's why I decided to take pictures of them side by side. You will be able to see the differences in terms of dimension of the phones below. All images are taken by Nokia N8 (unless specified).
The image above is taken using an iPhone 4s. It has somehow a paler color when compared on the image below which is taken using Nokia N8.
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| E71 , Xperia Arc S, N8 - taken using an iPhone 4s |
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| E71, Xpera Arc S, iPhone 4s - taken using Nokia N8 |
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| Xperia Arc S is noticeably larger dimension (and screen size) than X10 |
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| Arc S is thinner than X10 (around 25-35% thinner than X10) |
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| Arc S is thinnest at the middle and thickens on top and bottom (concave shaped) while X10 on the other hand is thines on the top and bottom and thickens in the middle (convex shaped) |
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| iPhone 4s , X10 , Arc S - on a glance, iphone 4s seems to be the smallest from the bunch |
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| Arc S on top, iPhone 4s on the middle and X10 at the bottom. |