To answer the title. Just had my first shave with a Schick injector. I see why people love them. Im not going to ignore my DE razors but l see a lot of use in the future for the Schick.
I have found injector blades at small mom and pop type pharmacies
IMHO, they are the best shaving tools on Earth. An E, G or J type with a Chinese Schick blade will provide you the best shave possible