I've been looking for a primer for months, and I finally settled on Kiehl's Micro Blur Skin Perfector - which I chose over Estee Lauder Idealist Pore Minimizing Skin Refinisher. I don't wear foundation, or a base of any kind, and I wanted a primer that improved and smoothed out my skin tone and pores without making me look too 'made up' . The Micro Blur does this perfectly, it lasts all day, conceals pores and I had no need to apply any pressed powder over the top. So far so good!
However, after 2 consecutive days of use my skin had a major break out, and I have dry skin! Weirdly, the break out was mainly on my forehead and not my nose (I had used it over my t-zone). I stopped using Micro Blur straight away and it took a week to clear up. I'm a little hesitant to use any more of it (I have nearly a whole tube unused...), and next time I will buy the Estee Lauder product which feels more 'tightening' rather than a pore-plugger, such as Micro Blur.
If you are completely immune to break outs, you may have more luck and if so it's worth the money.