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Personally, I switched to the new design as soon as the option became available and I never looked back. It is, in my opinion, immeasurably better than the old one: cleaner, more intuitive, less clutter. However, I'm only one of Facebook's 100 million users, and although some 30-40 million have already made the switch, the rest haven't, and they probably have good reasons for it. The "People against the New Facebook System" Facebook group has reached 220,000 members, which is another indication that the number of unhappy users is significant.
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