Hoffnung mentions some good points. A local witness also does the same. A couple of points they brought out recently were
In commenting on John 14:12 (Jesus followers doing works greater than him)
they said
We truly have done works greater than Jesus just as Jesus said we would. He began his preaching campaign at the age of 30 and continued working intensively for 3 1/2 years. Whereas many here have been preaching from childhood.
another time in commenting on Matthew 24:45 Who really is the faithful and discreet slave ...
they said: This is a marvellous verse for interrogating false religion as it's importance lies in the fact that it is a question. And this question can be put to all religions and they must provide an answer to Jesus Christ. Of course Jehovahs witnesses have already replied to this question.
edit: however if you feel that you would be letting your brothers and sisters down it is best not to use these tactics. the person who makes these sorts of comments has been fading for some time now and has come to terms with their own interaction with Jehovahs witnesses.