Funny this thread came up now as I just went to Sephora today & met a training supervisor who travels between many stores (lucky for me). Well, anyway, I have never used a primer (although I have LG's spackle, SB & I picked up Cinema Secrets primer at the NYC Makeup Show several weeks ago). Anyway, that said, we were discussing my makeup routine & my rosacea so she suggested Hourglass' new SPF moisturizing primer for rosacea, sensitive skin, acne, etc. So, since I went shopping with a bare face, I really put this stuff all over me to see if I would have any reaction. If I do, I'll get red blotches all over my face. And with rosacea, I can only use the non-chemical zinc & titanium dioxide suncreens. Well, I lathered this all over as generously as possible & I am pleased to say no reaction what-so-ever. It's free of all oil-free, sulphate-free, parabens-free, no chemical sunscreens, no animal testing, etc. After application it did noticeably quiet my redness as she said it would. Naturally, I haven't used this with any foundation so I don't know how well it acts as a primer, however, if you purchase from Sephora you do have 60 days to use the product & still return it.
So, here the link to this product on Sephora: Note, it's got a $52 price online, but I could almost swear that it was $45 in-store, which is still hefty!
Excellent rating & 200+ reviews.
Sephora: Hourglass Veil Mineral Primer SPF 15: Primer
Also, you may want to go to skinactives.com's forums for advice & support on skin issues. There are forums dedicated to acne & rosacea. I've spent many hours familiarizing myself with the additives she sells, reading the forums, reading up on rosacea, reading up on the various additives, etc. (PS, many of the gals on the QVC Beauty Banter forum order from her; btw, she's a chemist.) So, as soon as I use up all my on-hand skincare stuff through this coming winter, I'm going to make my own skincare so I don't have to deal with unnecessary ingredients & adverse ingredient reactions due to my rosacea & sensitive skin. And, it's a heck-of-lot cheaper to make your own -- with fresher ingredients. Some of her formulas have been so successful that at the behest of her customers, she has started making her own serums inaddition to selling the individual ingredients to make your own.
HTH!