This has always been an issue with major Android updates. Handset makers and carriers are scrambling to make their offerings different from the Android crowd. This is commonly accomplished by altering the core user interface, and also by modifying apps like the web browser to make them different.
This means that even when a particular phone gets an Android 4.0 update, it will be different from that shown off recently by Google that has everyone excited. While a device update may not be wildly different from what we've seen from the platform creator, you can be assured it will deviate from it when it finally hits different devices.
You've probably seen this happen with past updates. A common scenario is you pick up a device running Gingerbread and notice immediately that the browser is different than that on your own device. Maybe the bookmarks are handled differently, or the page rendering is not quite the same. These are not deal-breakers by any means, but they indicate that the Android version running on different devices is not quite the same.
Hopefully partners won't mess around with Ice Cream Sandwich too much, but it's a safe bet that they will make it a little unique to stand out in the crowd. If you're lucky, the features changed won't be ones that caught your eye in the Google presentation of ICS.
You can avoid this customization of Ice Cream Sandwich by going with a Google Flagship phone. Google makes the partners agree to keep the full stock OS on these phones. This is why I own a Nexus S 4G, the current flagship phone from Google until the next is available (Galaxy Nexus). Google has already promised my phone will get ICS quickly, and I know I'll get just what has been shown off to the faithful.
Other Android phone owners will turn to the homebrew crowd to not only get ICS as early as possible but also to get a relatively stock version of it. This works well and many owners swear by custom ROMs, and rightly so.
It's says a lot about a platform when device owners who actually get a major update, may get one modified from the official release version. You may get Ice Cream Sandwich, but will yours have all the sprinkles found on the official version?
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