Poro prism binos are not as easy to water proof, are bulkier, have better depth perception, and can be made to be clear and bright at a lower cost then roof prism types.
Roof prism binos need good phase coatings to be as clear and bright as poro types. They are easier to make water proof and have less bulk.
Jon at The Optic Zone has 8x42 poro prism Bushnell Legends for about $109. I wouldn't get binos with less than 7x magnification or with less than 32mm objective lens. The Legends have rain guard and it really works.