being a sunglass hoarder, and on the road, driving from appointment to appointment every day in Southern California, I have learned what I like about sunglasses.  My favorite style is a double bridge, rectangular aviator.  Most top brands offer them.  Rayban, Maui, Oakley, Revo, Kaenon, Smith (sort of) Prada etc.  I've worn Serengeti Firenze for about 3 years and learned that these polarized, dark amber-ish glass lenses are the darkest available and are the very best
I love the serengeti firenze, and they're still my benchmark for every aspect of sunglasses. Fit, finish, clarity, design, quality and darkness.
The palladio is a newer model that use the same exact lens shape and size.  However, they're held by a very light and flexible titanium frame, with light and flexible temples, that just happen to be the perfect length.
The frames fit my face perfectly, right out of the case.  No bending the nose pieces in, out, up or down.  The light, and flexible frames allow you to slightly flex them apart and rest them on your nose.  The nose pads "grip" your nose, ever so slightly.  This makes the frames lightly "grasp" your face, rather than just resting on your nose and ears.  They're still so light that you don't feel them on, and they don't dig into your nose.  They sit very close to the eye, but still don't rub my eyebrows, which smudge the lenses.  These are just as light as my polarized oakley jawbones I use for riding.
These lenses are Polar PHD 555nm, rather than glass 555nm.  The tint vs the Glass lens is slightly less amber, but just as dark  The clarity is absolutely razor sharp.  Somehow, still sharper than the maui jim, and the Kaenon's I've returned for comparing apples to apples, I did not expect these lenses to be superior to the maui or Kaenon, as they seem to be the best plastic lenses  They're as dark as the glass 555nm, and might just darken slightly more quickly than the glass version, although I personally do not care.  i just want them to be polarized, feel and look great and get as dark as possible.  Serengeti states that their 555nm polarized lenses go down to 8%.  Only Smith (that I know of) offer polarized optics that dark.
The anti reflective on the inside of these lenses are just as effective as the glass 555nm, but do not appear as blue-purple when holding them in your hand.  Anti reflective is very important to me.  I frequently drive with sunroof ope, which tests the effectiveness of a sunglass, and it's inner anti reflective properties more than anything.
Cleaning these is actually easier than the firenze.  when you rub the glass with finger and thumb, the flex of the frame allows the cloth to reach under the nose pads easier.  So they clean up slightly quicker.  Another small detail, but one that enhances caring for them properly.  It remains to be seen if the superior scratch resistance of glass will be retained by this model.
The past week here in LA has been very record sun and warm, which is always best when new shades arrive. i am enjoying the light and flexible nature of these frames very much.
If you visit the serengeti website, you'll notice that they've added some new models.  They just keep getting better and better.  I am very suprised that they don't capture more market share than they do.  There really is no better brand of sunglass anyway you think of them.  Italian style and flare, incredible fit and technology, superior polarized optics, and a very good value.