I call that an unsubstantiated claim. Also, total nonsense.

There's nothing in agile that makes the work inherently buggy. If anything, it should be less buggy; (documentation is another matter). Done right, agile minimizes schedule pressure so you should have the time to do the work you need.

I've spent years thinking about Agile and development in general. I'm no apologist for the methodology: see my post from just this morning: http://deathrayresearch.tumblr.com/post/27257008711/when-agile-jumped-the-shark. Some aspects of Agile are better than others, but overall, the methodology is based on sound principles. Most notably, there are many short feedback loops (unit testing, continuous integration, short cycles, customers on the team) that decrease the opportunity for hidden problems. This is extremely powerful. That it's used to sell services is undeniable, and their are aspects that strike me as wrong, but this is a good methodology overall.