Because I have extremely extremely sensitive skin (meaning if I put on a foundation or finishing powder that isn't compatible with my skin, I immediately break out or get tiny bumps that appear all over my skin) I've been forced to stick with certain powder foundations (vs. liquid foundation).
I began using Bare Escentuals years ago, but switched to Benefit powder foundation when I discovered how infinitely better the quality of Benefit powder foundation is. Recently I've started using Bare Escentuals again as my daily foundation, using Benefit powder only on special occasions, etc., however, because I've realized that it is the only foundation that actually clears up my skin. (Benefit was better than most foundations on my skin, but it still gave me tiny bumps if I wore it for too long a period of time.)
So here are the pros & cons of Bare Escentuals:
--actually cleared up my skin, preventing me from breaking out and actually giving me smoother skin
--cheaper than most foundations -- esp, if you buy it off of ebay, you can get it for ~$16
--compared to Benefit powder, the powder is not as finely ground
--very light coverage - for better coverage, you should intensely moisturize first or use a very good primer, especially if you're going for that polished, perfect skin look rather than the bare-skin-no-makeup look.
--pretty drying - it actually gives me creases on my forehead and along my nose... the most oily parts of my face! I feel like this probably helps clear up my skin (by soaking up the oils) but still, I'm 23, I shouldn't have any wrinkles yet! I've started intensely moisturizing those areas prior to applying foundation
--color is meh - it's alright.
--without reapplication of the mineral veil throughout the day, your face doesn't look as smooth and flawless as it would with benefit. pores may become more visible if you tend to sweat more.
Despite its flaws, I continue to use BareEscentuals on a dailly basis. It's cheap, keeps my skin clear, not great for special occasions, but it works alright. I think that it's best for those who are starting to wear foundation for the first time, or for those who want a bare-face, natural, no-makeup look. If you want that perfect, porcelain-face look, this probably isn't for you. Just know that there are much much better foundations out there.