It's often difficult to determine where to draw the line between advertising claims and puffery.  A recent case from the federal district court in New Jersey provides some helpful guidance.  

In Stern v. Maibec, the plaintiffs sued a shingle manufacturer, alleging that the shingles did not perform as advertised.  The plaintiffs asserted claims for breach of warranty and engaging in deceptive practices, as well as other claims.  

When promoting its shingles online and in its brochures, Maibec made claims such as "very durable and requires very little maintenance" and "they are engineered to be so durable, you just might consider them high tech." 

On a motion for summary judgment, the court considered whether Maibec's statements were puffery -- "an exaggeration or overstatement expressed in broad, vague, and commendatory language."  When making this determination, the court considered several factors.  First, the court evaluated the "vagueness" of the statements" -- whether they failed to describe a specific characteristic of the product.  Then, the court determined the "subjectivity" of the statements -- whether the statements can't be measured on an objective basis, such as by reference to clinical studies or comparison with the product's competitors.  Finally, the court considered whether the statements "were capable of influencing Plaintiffs' expectations."  

The court found that statements such as "tougher than ever," "engineered to be so durable that you might consider them high tech," and "guaranteed to last" were not puffery, because they emphasized the shingles' durability and low maintenance, and that this "could certainly influence Plaintiffs' expectations when deciding whether to purchase it."