I've used Bare Minerals and Everyday Minerals. I prefer Everyday Minerals for two reasons: 1) the price, and 2) the variety of shades that EM offers. They offer shades for 3 different skin tones: warm, cool and neutral. I'm a true neutral light, and BM's light is too warm for me, as well as slightly too dark. This requires me to mix it with Fairly Light, and its still too warm. With EM all I need to do is buy 1 shade and it blends perfectly with my skin. They also offer different finishes, I prefer the matte finish rather than the glow. It works better for my combination/oily skin.
I know other people felt the variety of colors was too daunting to sort through, but I've been using makeup for a long time and I'm pretty good at picking out what works best for me. If BM works for you and you like it, I'd stick with it. If however you are like me and weren't completely satisfied with BM, give EM a try!