Ski goggles almost all have some tinting that are not ideal for your light conditions. You'll want clear or something glare-cutting. MX goggles are fine. Smiths, Oakleys, etc. are expensive. Scott makes some real budget MX goggles but you did not hear that from me. My personal preferrence is Dirty Dog from New Zealand.
MongoosePro DH, Dart custom road bike, .243 Racing FR street bike
I use Oakley O-Frames in snow camo (I am so hardocre man). The best lenses I have used were an orange iridium lens. In the bright light they cut out glare and in the shadows they really highlighted any variations in the ground. Not only were they good to wear, they looked awsome. However standard clear lenses are easily good enough.
Different goggles have different shapes (some take your helmet with you when you get them to make sure they fit well). Also the main difference between Snow and Dirt goggles are that snow goggles have more ventilation to stop fogging and they also have double layer lenses to stop fogging.