Do I want pressed powder mineral foundation or loose powder mineral foundation?
It comes down to your personal preference in the finish and your skin type. If you have naturally oily skin, it can be best to go for a loose powder. Pressed powder foundation is milled to a fine powder compared to a loose mineral foundation that has a much larger particle size. Due to the fineness of the particle size, it does tend to build up on the face more. That can cause a chalky or ash like finish, so you have to be careful not to overapply. If you have oily skin, it combines with the makeup easier, and you end up with a very shiny face.
As loose powder foundations have a larger particle size, they do not cling together as easy as the pressed powder foundations thus it is harder to over apply. With the larger particle size, it is also more difficult for oil to penetrate the cover. On the downside, a loose mineral foundation can be very messy. So you could say pressed foundations are more car and travel-friendly.
Purepressed and Amazing Base are both high-quality pure mineral based foundations. They both have a natural SPF factor with broad UVA/UVB protection, however; please do not replace the use of a quality factor 30 sunscreen. Think of it as basic insurance but no substitute for full cover.
It is worth noting that Amazing Base is darker than Purepressed. If you currently use Amazing Base and looking to try Purepressed as a basic guide, it is about two shades lighter.