I got our magicbands for our Feb 1st check-in last week. They were the new style. Unfortunately, the screws on the inside of the band caused my wrist to break out in hives - I tested before going to Disney because I have a pretty bad metal allergy. My skin eats through clear nail polish, so coating them isn't a viable option. I was afraid this would happen so bought an old-style band at the end of November just in case, but I wanted to give people a heads up. The accessories are not available yet to put them into a keychain or lanyard, but Disney told me that the resorts may have a supply of the old bands to swap with if you also have a metal allergy until they make accessories available for purchase, though they can't guarantee if the bands will be colored or just gray.
On a positive note, you can use a small eyeglass screwdriver to remove the screws... you don't need a special screwdriver.