The only problem with the S Series is in year two when it becomes an old phone. The non-S Series phones stay current and relevant for two full years. Of course if the new design is nasty then nobody on the S cycle would mind that but the i7 is expected to lose bezel size and possibly even the home button. In my opinion the 6 Series is a poor design with its big bezels, weight, and protruding camera. Still, there's no disputing that the 6S will be the best iPhone since the iPhone 5 and will finally get the RAM that the 5S should have had. I don't see any real negatives to getting a 6S as it's a massive performance increase.