I have four Oakley competition models, however I find myself turning back to the Defender over and over again because the lens is perfect for low light to bright sunlight. Since I start most of my rides at sunrise and continue through the morning I need a flexible performance based sunglass. The Defender delivers and has now for almost two years.
I just wore the COLOR IMPACTX-2 PHOTOCHROMIC CLEAR TO LASER BLACK lenses for a Triathlon and they were useless. I started my ride in low light at 8 am and they were fully dark throughout the whole ride and stayed fogged up the entire time. I ended up having to ride the last 45 miles with out glasses because I couldn't see the road or other riders. I didn't even bother bringing them on the run and finished the race with out glasses at all. I'm sure they are a good fit for some but they really let me down when I needed them.
This will be a review of *both* lenses...
A big selling point for me was that totally transparent lenses for riding at night were available here. Not everyone does that. These were clearer and offered better light transmission than what I had used previously. Less internal reflection with the Rx adapter than I had before- net gain.
The ImpactX-2 photochromic lenses that came with the Graphene Defender? They are a cooler shade of gray than I have experienced before, but adapt quickly and are *so* good for all conditions short of total darkness, that for me, any additional lens choice would be simple vanity.