Straight to the chase: Julbo's lenses are simply inferior in quality & performance to Smith & Oakley. They scratch too easily, and can't define the fine contours of bright, convoluted snowfields, much less the depth, shadows, & layers of an evergreen forest like Smith's better rose-copper mirrored tints, or Oakley's Irridium lenses.
I bought the Aerospace goggles w/ the Zebra photochromic lenses (7-42% VLT) as a replacement for a broken set of Smith Phenoms w/ Ignitor Mirror (35% VLT) lens. This proved to be a very poor, and costly decision. In a word, it's irrelevant that the Julbos are photochromic, the contrast is so poor that I simply don't want to wear them, regardless of how broad their nominal range is. The "reaction time" claimed by Julbo is also irrelevant: contrast and light transmission is so poor in shaded areas that even stopping & waiting for the goggles to adjust is pointless. What is more, after a single day of use & careful handling, these Julbos already have more small surface scratches than any of my Smith or Oakley goggles that are several seasons old.
Using the Zebra photochromic lenses in the open on a bright bluebird day in Lake Tahoe, they produced a tolerable, albeit muddy view of the convoluted & rocky terrain I was navigating. As soon as I dropped into a familiar, wooded zone, however, I realized that these goggles had no place in my pack: I could make out the trunks of trees, but due to Julbo's poorly-blended, flat, gray-gold tint, I could discern next to nothing of their layered branches, or the rocks, deadfall, and critically sparse snow coverage below.
I had hoped to benefit from Julbo's novel vented frame design on warm spring days at the resort & in the backcountry, but even if I knew I were spending an entire day above the treeline, I would still opt for something (i.e. anything) else with better contrast. Julbo's Zebra tint reminds me of the mediocre green-gold Uvex lenses I used in the 80s, prior to discovering Smith's game-changing RC36 tint.
Forget the frame, the lenses just don't measure up.