The Radarlock XL's fit much better than the old Radar XL's (I own both) and the lens swapping feature is excellent. I can remove and replace the lens almost without touching the surface and putting fingerprints all over it, and it doesn't give me a nervous breakdown thinking I'll break the frame like the old design did (for the record, the frame has yet to break on my old Radar XL's and I have swapped lenses plenty of times). As for the photochromic lens, I'm satisfied but not over the moon about it. I mostly wear these mountain biking, and it seems like the brim of my helmet keeps the lens from fully converting to its darkest tint, even in bright Moab sunlight. If Oakley had included a dark tint spare lens, like Black or Red Iridium, these sunglasses would be perfect. My only other complaint is that while the smaller, more rounded lens performs slightly better and looks sportier, it loses a bit of the square Terminator style I love about the Radar XL. Bottom line, I'm still giving these five stars for function and fit.