With the String "+=&/()!" (without quotes) nbvcxz returns a score of 4/4, entropy of around 35 and 7 brute force matches with an entropy of around 5 each. Which seems kinda overrated.
The online demo on the other hand returns a single brute force match with only a score of 2/4. Which seems more appropriate for a password of only 7 chars. I'm sure even some precomputed rainbow tables go up to 8 normal chars (letters, digits and regular special characters)