I have transitioning Rudy Projects that I bought during the crazy 50% off sale at Terry last year. I was eyeing the Tifosi ones at the time, when the opportunity to get these popped up.

They are AWESOME. I particularly like them for hiking where the shade/sun changes are so numerous. I haven't worn them mountain biking, but I bet they'd rock for that. The only time I've found that they didn't get dark enough was when the sun was very low in the sky but still directly in my eyes. I have no idea why, but they just didn't go dark. Weird. Luckily, that doesn't happen all that much. They are great for shady decents, though!