I think both, eyelid and mineral eyeshadow primer, have the same amount of product and they are paraben free.
What e.l.f. says about them:
eyelid primer: "Preps your eyelid for smoother, longer-lasting and crease-proof eyeshadow. The ultra sheer nude color works to increase eye colour longevity. The lightweight liquid formula quickly absorbs into the skin for comfortable wear."
mineral eyeshadow primer: "This gentle and completely sheer Eyeshadow Primer has key vitamins A, C and E to help prevent aging and moisturizes the skin. The formula glides on easily and disappears instantly to create longer-lasting, crease-proof eyeshadow. The Mineral Eyeshadow Primer is designed to be used with your favorite mineral eyeshadow to provide ultimate staying power for beautiful and vibrant color that lasts. 100% mineral based with no parabens, no preservatives and no chemical dyes."
The applicators are the standard for eyeshadow primers, the mineral primer's applicator is slightly bigger than the eyelid primer's.
I got both primers in sheer. The e.l.f. eyelid primer comes in another 3 colors whereas the mineral eyeshadow primer only in sheer.
As you can see from the swatches they look the same and they both blend easily. They dry to matte finish but the eyelid primer has kinda off-white color when it drys which isn't noticeable pretty much at all. Texture wise the are almost the same with mineral primer being slightly smoother.
One difference you will notice when you open them is that the e.l.f. mineral eyeshadow primer has a really nice buttery smell and the other almost hasn't any smell. Personally I prefer the buttery smell :P.
I should probably choose another eyeshadow, less pigmented but anyways. As you can see there is a noticeable difference been the swatches without primers and with them. I would say that the e.l.f. mineral eyeshadow primer is a bit better with helping the eyeshadow payoff. Although they don't do tremendous work with boosting the eyeshadow payoff, they do help a lot with staying power of eyeshadows. I have noticed big difference when I'm wearing either of the e.l.f. primers.
That's how the eyeshadow looks after about 7-8 hours. I didn't use the same eyeshadow for the eye makeup and swatches!.
I must say that the color pretty much didn't fade at all so thumbs up for the primers.
Overall I would say that they preform almost identically with e.l.f. mineral eyeshadow primer being slightly better, at the end is up to you if want to pay £1.5 or £3. To be honest next time I will need a new primer I don't know how I will decide which one I will buy :P.
Have you tried any of these? Which eyeshadow primer are you using? Let me know in the comments below.