Mine is a Preformance tool W80670, I probably got it at a auto parts store, O'Reillys. probably done over 3 dozen flares with it. Haven't had a problem.
I've found , as with a lot of other things, practice makes perfect.
I would suggest the Ridgid tubing cutter. I have the close quarters one and the standard size. Don't cheap out on the cutter.
On edit, I haven't tried it on SS tube.
2nd edit. I've only flared 3/16" brake line with this tool. I just tried a 5/16" line, the small die wouldn't fit in the tube. The next size down was too small.