In general roof prism binoculars are tougher, but I have Porros from the 1950's to 1980's that have been hunted hard and are still in perfect collimation.
The big problem isn't so much toughness as waterproofing. It's easier to seal roof-prism binoculars, so until most Porro prism designs weren't water-resistant. But all the more recent Porros I've seen have been sealed, and work fine. I've mentioned before here that I used a 6x30 Leupold Yosemite to help me take a grizzly in Alaska a few years ago, and the Yosemites (despite their price) are sealed.
Most Porro-prism binoculars do have optics equal to more expensive roof-prisms.
