I've used it to make some 90 and 180 degree turns in ACR copper tubing, perfect curve as long as you know how to use it.
Used this all week to bend tubes, and used all three sizes. It works great, the action was nice and smooth.
This tube bender is great. It has a nice quality, and it shows, but it does the job without kinking the pipes.
I had no issue getting my steel parts bent, and it worked better than my old one plus it comes with accurate margins.