I have had an SM7B with a Focusrite Scarlett interface for years. It works great; I can only recommend it. The SM7B definitely needs an interface because very little level comes out of the mic. Even with an interface, you're at the lower level.
This is absolutely necessary with an SM7B but if you want a Shure without a mixer etc. I would recommend the Shure MV7. You can connect it directly to the computer via USB.