There has been a post on this topic recently that you should read. Have a search.
As a general point though on the text that you have, I would suggest you avoid starting off by saying what others do wrong and focus on what you do right and let punters figure out the implication. I know that negative advertising is "in" at the moment but the results from it have not proven to be that great (ironic backfire) and, at the extreme, American style damning of the competition is unlikely to ever be a big winner in the UK.
Bottom line: keep it positive, say what they should look for and why it is a benefit to them and confirm whether or not it is part of your standard offering or an option when they are ready.
Stuart