Get the silicone case, believe it or not after about 2 days of use, it picks up the oils from your hand and daily usage and it loses that lint magnet factor immediately.
The Apple silicone case is not like most silicone cases.
Take my word on it, when I first got the black silicone case for my 6 Plus the lint was driving me CRAZY. However after a couple days of use, it gradually went away and after 2 weeks my case still has a nice grip to it but it doesn't pick up ANY lint at all.
The leather case is very unforgiving unless you have black. It stains easily and picks up blemishes.
You just have to break it in, and the people who returned it, I don't think they got the chance to do that!