Depends on the target, id consider something like Stuxnet to be top-notch given: - Delivery - Target resources (another state) - Target defenses (I like to think that the iranians had good security) - Stealthiness - Target architecture. Its easier to write something for Android (for which we have the OS open sourced) than for siemens PLC

But as others say, you wouldn't want to advertise your exploit as top-notch, as it will bring unwanted attention

Nothing, because blackhat activity disqualifies itself from such a label. Recognition is actively withheld since it'd encourage some bad actors. Same reason malicious software is always given a different name even if one can be found in it.