Thanks y'all. I'll go with tempered then.
Caveat - The tempered is stiff enough that if you are not careful using it, from personal experience, you can draw blood if you poke your self with the end of that stuff.
Also resist any urge to anneal it. When you take it off the spool it will seem too springy to use but it has a strange behavior in the sense that if you wind it tight on a mandrel it will stay tight.
Other than that IMHO it makes life a whole lot easier.