It's great! I've had community members point me in the right direction after already "solving" it incorrectly. It really makes you think about it. You have to expand your test cases and really come up with a better solution.
Not to say it isn't difficult especially if you expect the problem to be described perfectly accurately.
The problem is the example is actually
eightwothree
which comes out as83
so if you replace from start to finish the example passes but the solution is incorrect.