Printify's print provider partners are not all the same. They may use different printer technology and printing methods. They may print on different materials as well. Even if they are printing on the same garments and using the same print technology, each print provider will have performed their own unique tests to achieve their desired color output.
In addition to having different garment options, print providers also have different print areas. This means that some print providers offer larger print areas as well as more print areas in general including sleeve printing, neck label printing, and printing on both sides of the garment.
Merchants are encouraged to perform their own research on the available print provider partners and to choose the provider that best suits their needs. More information available here.