Re: need advice-which Apple case for silvery phone
Ultimately you need to fit your personal tastes.
I see lots of choices and what people do because of my IT admin work. I don't like big thick cases and see our delivery and manager staff break phones with them as much as with a decent rubber/soft case. Because of that I've liked the Belkin Grip and Incipio NGP for protection and not being too fat.
For personal favorites I just had my mind all messed up by going from years of black to a white and bigger 6s Plus. I have the Apple silicone in "Stone" and got the brown leather over navy knowing it will look very used. I wear black a lot, also blue and khaki. The brown just looked more neutral with black, and nice in general. The Apple leather case lets the large phone slip in the side pocket (carpenter jean style) pants I wear for casual times.
There is a style of case that's barely more than a skin that is nice - Spigen, Caudabe and Ozaki make them. My experience is these will help you avoid a scratch but they offer little or no drop protection.
The thin Apple silicone and leather cases I've got with past phones have had many drops where they stick out enough to protect the screen but they're also not so in the way when you use the phones.
Now I wish I could say I'm as sold on the 6s Plus he he he.... It's superior for the amount of reading I do, and two business apps I use through each day. It's also a lot heavier. It may also be silly to complain about the size considering my work used to require carrying a bag phone and Motorola "Brick".