Our method performed better in terms of grammaticality, equally well in meaning preservation, and worse in diversity, but it could be tuned to obtain higher diversity at the cost of lower grammaticality, whereas it is unclear how the system we compare against could be tuned this way.
an advantage of the paraphraser we compared against is that it always produces paraphrases; by contast, our system does not produce paraphrases when no paraphrasing rule applies to the source sentence.