It can't decide which of the four INXXs I am, which means it's probably the most accurate function test I've taken. It's pretty fun, too.
No, none of the tests are really particularly accurate because they rely on self-report. They're only as accurate as you are honest with yourself/informed about the topics.
The fact that it "can't decide" which of the four INxx types you are simply reveals that
you can't decide which of the four INxx types you are, not that you're just magically 99% borderline between all four. People in general vastly overestimate how "borderline" they are because they want to sound balanced, but in reality, being truly "on the border" between any dichotomy other than I/E is incredibly rare/almost impossible. Chances are you don't understand enough function theory yet to have accurately determined your own type--this doesn't mean you don't have one.
P.S., in my self-described expert opinion based on about four of your posts, my preliminary guess is INFJ. But this really can't be tested and there's no way for me to find out how accurate my assessment is without spending a LOT of time talking to you and getting to know you. You answer 70 pre-formatted multiple choice questions and expect to get an accurate answer on your inner psyche? Not happening.
I'm an ISFP according to this. Barely though.
Come on, people--you can't test psychological type accurately. You're wasting your time. You need to just continue studying functions and the way they apply in real life, not keep searching for the "one perfect test" that will finally illuminate everything for you without you bothering to learn all the concepts.
Hint: Nobody ever really knows what his own type is without significant background in typology. The "tests" are all garbage; move on.