1. A complimentary remark is nice,but a complementary remark is more useful Editing by Professional Editors
2. A complimentary remark is nice, but a complementary remark ismore useful Among pairs of words that are often confused is the pair complimentary/complementary. Complementary is not only far more common in scientific writing but also has several specific meanings: a complementary sequence of a piece of DNA, for example, or a complementary angle (which, together with its partner, adds up to 90 degrees). Then there is complementary medicine, also known as alternative medicine, which refers to treatments other than those followed in or recommended by the traditional Western medicine.
3. A complimentary remark is nice, but a complementary remark ismore useful Complimentary, on the other hand, either refers to praise (as in "The reviewers complimented the researchers on the originality of their approach" or "The poster won many compliments for its attractive design and clear presentation of information") or to something given away free of charge (as in "Complimentary copies of the special issue of the journal were distributed at the conference" or "Complimentary passes for the exhibition are available for the participants").
4. A complimentary remark is nice, but a complementary remark ismore useful Thus, while it is nice to be complimented, a complementary remark - one that reinforces what is said or presented - is even more welcome.