[greedo]

It depends on the goals of the launch. If they met their goal criteria, and sticking the landing wasn't one of the goals, then it's a success.

[qayxc]

I'm pretty sure a successful landing was one of the goals. It just might have been a "nice to have"-kind of goal.

During prototyping there's only one type of test that isn't a success: a test that fails for a previously known reason (e.g. repeating a known mistake or some external factor like earthquakes, flooding or weather) and that you learned nothing from.

[greedo]

Elon explicitly tweeted the mission's goals:

"Goals are to test 3 engine ascent, body flaps, transition from main to header tanks & landing flip."

So the SpaceX team went four for four...