I have alligator straps in Black, Blue and Cognac. The crocodile straps are black. All have a matte finish and white/cream contrast stitching. These straps are all hand made in Italy.
The crocodile straps have "high padding" in the so called "Brietling" style. The alligator straps have a more modest padding.
I wondered about the blue alligator strap, but I really like the blue alligator on the stainless steel cased prototype Ka La watch with its blue hands and hour markers. I will have to order some more of them!
The cognac looks good with both the stainless steel and the PVD rose gold cases. I will have to try a cognac strap and rose gold case with a silver dial and see how that looks.
The black alligator and crocodile straps, as expected, look good with everything. Crocodile is basically as nice as alligator but it lacks the distinctive "grain" of real Louisiana 'Gator.