Q: What's the difference between a 600 and an SX-70
A: The 600 is more entry level camera, they're easily identifiable by the boxier shape. Sometimes they are known as "Box Polaroids" The SX-70 was sold as a more professional model
back in the day. SX-70s have sharper, manually focusable glass lenses. As apposed to sometimes fixed focus lenses on the 600.
Q: Where do I get film?
A: Film is readily available online on Amazon and from Polaroid Originals' website. You can also get it locally at Target, Best Buy, Walmart, Microcenter, Meijer, and at some photography stores. Search for either 600 or SX-70 Polaroid Originals film online.
Q: Is there a difference between 600 and SX-70 films?
A: Yes, 600 film is a "faster" film meaning it needs less light than SX-70 film in the same setting to get the same exposure. This leads to faster shutter speeds on a 600 camera. 600 film is also easier to get locally. This is a major advantage of having your SX-70 converted to use 600 film.