Default nearly identical case comparison

I've been looking at cases being offered from amazon retailers and while I like the looks of them, I'm a little hesitant due to the talk of the effects of magnets on the spen. My first question is: Are the keyboard cases that have a leathery appearance made by Omoton, Moko, Khomo, Supernight, eWonder, Ivso, QQ-Tech, Photonic and Fome all essentially the same product with only slight cosmetic differences? If this is the case would I be correct in guessing that all of the manufactures that make this kind of case have the same problem with the spen? Or is there something I'm missing that sets some of these apart? I have noticed that some of them use slightly different keyboard designs.

I am asking this as my introductory post to this forum because to my knowledge, a comparison like this has not been done before here (I did look).

Hopefully once the URL restriction is lifted, if people wish I can add a list of the different items that I see a remarkable similarity to. For now, if people are wanting clarification on what exactly I'm talking about, look up "MoKo Bluetooth Keyboard Cover Case for Samsung Galaxy Note 8.0 inch GT - N5100 / N5110 Android Tablet, BLACK" as an example of what I'm talking about. Aside from color and texture differences, the others I'm asking about are largely the same.