I love them and have managed to accumulate quite a few:
From right, counterclockwise: NYX Eyeshadow Base in White, Hourglass Mineral Veil primer (trial size and Sephora 100 pt size), Hourglass No. 28 Primer Serum, Too Faced Shadow Insurance, Wet 'n' Wild Fergie Take on the Day Eyeshadow Primer, Urban Decay Primer Potion, L'Oreal Magic Perfecting Base.
I love a good eyeshadow primer! I like all three featured here. The Wet 'n' Wild primer was a surprise hit and I'm glad I tried it. It works just as well as my mid-end counterparts and is a good deal for the budget-minded.
On the other hand, I don't perceive any added benefits in using a face primer. I tried the Hourglass primer after reading the Beauty Reductionista's raves for it here. It feels good going on my face, and doesn't make me break out. Unfortunately, my makeup doesn't act any different when using this or just my Olay sunscreen moisturizer, so I won't be repurchasing. I've already swapped away all my other face primers as of this post.
My plans for this stash is to hold off on buying any more primers until my remaining ones are used up. I love to try them, but I really don't need more than one at a time.