If it's an Apple product I'll always buy the stuff they sell at the Apple store simply because they have good quality ones and I don't want to shop around since Apple related stuff is always more expensive...but if it not Apple I will shop around just because it's easier to pay less when buying non Apple stuff...
My phone case has Sonic and Shadow on it, I got it from Amazon not too long after I got my phone a couple of years ago. The image of the two is unfortunately starting to peel off though. :\
I have a phone case for my iPhone, the brand being Onn and the color being black. I think it is very important to have a phone case where the screen can crack easily when dropped because I've dropped my phone countless times. I only switch out my phone case when it becomes damaged.