When in pursuit of a new client, don’t bag the competition. Remember that you have competitors; your prospect has alternatives.
By putting down the competition you run the risk of being seen as unprofessional, and perhaps a desperate salesperson making a vain attempt to make yourself look good. Politicians do it all the time – does it make you trust them?
You will soon break trust if your prospect has previous good experience with your competitor too. All this could result in you being taken off the prospects list of alternatives.
You should however be asking what alternatives the prospect is considering so that you can position the value of your offer or solution. Differentiate from your competition by focusing on the value you can provide to meet the prospect’s decision criteria and there will be no need to sling mud at your competition.