Stainless Steel
Stainless Steel has a coefficient of 0.00094, less than one-sixth of Nickel's.
This means that SS can not be properly used for TC without adjusting the coefficient - its resistance increases with temperature too little for normal mods, that are expecting Ni200, to use effectively.
Some people have vaped SS on normal TC mods, and it does somewhat reduce dry hits, but it will still burn cotton. To use it effectively, a coefficient adjustment is necessary.
Once the coefficient is adjusted, Stainless Steel works well - no burnt cotton. However my testing thus far has still required a temperature offset, albeit not as much as people have had to do with Titanium. When using the Infinite Nickel Purity feature, I have set an offset of around 50°F when using SS.
The advantages of Stainless Steel versus Ni200 are the same as for Titanium - micro/contact coils, higher resistance ranges, stronger. The advantages of SS versus Titanium is that it's much easier to work with - malleable, easy to coil. It is also readily available, and cheap. Crazy Wire/The Mesh Company in the UK sell SS 317L under the brand TMC.
The safety aspects of it are unknown at this point in time, though theoretically it should be safe at TC type temperatures (and perhaps safer than Ni200, though don't quote me on that!)