There's always a backlash with leaks but this is uglier than every other iPhone leak in history. The iphone 4 was gorgeous from the get go, the iphone 5 was sorta dumb looking, but this is extraordinarily bad.
Short memory. When the iPhone 4 leaked I remember people claiming it couldn't be real because Apple would never do something as ugly as that. Then when it shipped and people got to hold it and used it in person their opinions changed.
And when the 5 leaked people said the breaks were clearly something Apple would never do and therefore the leak was fake, but when it shipped those breaks became the iPhone 5's trademark.
Now, let's examine the iPhone 6 here: I think it looks good. I like the curved/moulded shape and I think the breaks are a very considered and deliberate design decision. They serve a legit purpose and therefore they don't try to hide themselves. And furthermore they are colour coded, so they work well. They are not artificially trying to look 'silver' to really blend in, they are admitting their own material construction and being true to the material they actually are; a very design centric choice and not tacky at all.
I like it. Out of the 4, the 5 and the 6 leaks I like this design the most.
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This probably is the non-anodized "raw" shell. Once finished those lines will blur away or be hidden completely by whatever existing/new and improved process they use to anodize/finish the shell.
This is a finished back, and it's anodised. The breaks look good. It's seeing them in isolation which is turning you off them. They are beautiful.