I've got Fire Iridium on my Splices for bluebird days. Light transmission on that is about 12%. I love them, but that's about all they're good for. The mirror effect is not just on the outside of the lens, however. When you're wearing the goggles, it transitions from red to yellow to blue/green to yellow to red (from left to right) on the inside of the lens as well. It doesn't bother me that much, but I thought I'd point it out since most people assume the color-changing mirror effect only works looking from the outside in. For bright days, basically any iridium lens (aka mirrored) would be a good choice.
I've got HI Yellow (83% transmission) for the cloudiest and foggiest of days. I've never used clear, but I would think the yellow provides more contrast and highlights. For everything in between, I use the good old Persimmon lens (62% transmission).
