Size is 80 percent of the reason to buy an iPhone 6s Plus. If you're really into video recording, video viewing, or mobile gaming, or you just want a big screen because you have tired old eyes, you'll want to buy the 6s Plus instead of the iPhone 6s. I think most people will be better suited by the smaller smartphone, but it's worth paying attention to that other 20 percent. Excellent optical image stabilization for video capture and faster LTE speeds make the iPhone 6s Plus our Editors' Choice for phablets on AT&T.

I need to start with my bias: I know the phone industry as a whole is tending toward huge phones, but I still think of smartphones as primarily a one-handed affair, and so I think of the iPhone 6s (and the Samsung Galaxy S6) as the default size more than their bigger brethren. In terms of iPhones, sales figures seem to bear my prejudice out: last year's buyers went for the smaller iPhone 6 model in an 80/20 split.

So assuming most people are going for the smaller (and excellent) iPhone 6s, why buck the masses and buy bigger?

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Pricing and Physical Design

The iPhone 6s Plus starts at $749 for a 16GB model. The 64GB model costs $849 and the 128GB model I reviewed costs a jaw-dropping $949. It's worth it to spring for at least the 64GB model—16GB just isn't enough for all the pictures and videos you'll likely be taking with this phone.

From a design perspective, the iPhone 6s Plus is mostly like an iPhone 6s. It's also mostly like an iPhone 6 Plus, of course. At 6.23 by 3.07 by 0.29 inches (HWD) and 6.77 oz, it's slightly thicker and heavier than the iPhone 6 Plus (an increase of 0.01 inch and 0.7 ounce), but not so much you'd notice. It's a big phone. I'm not going to dwell on that further.