From Longman Dictionary of Contemporary Englishbe a matter of opinionbe a matter of opinionused to say that people have different opinions about something, especially when you yourself have a negative opinion Whether or not he is any good as a manager is a matter of opinion. → matter
Examples from the Corpus
be a matter of opinion• Whether Innocent could have achieved his ends earlier or by better means must in the final analysis be a matter of opinion.• Many of these answers are a matter of opinion; some issues will matter more to some people than others.• Deciding which bag is easier to carry is a matter of opinion.• How successfully it is done is a matter of opinion on the part of the individual reader.• It is a grand conception; whether it is a useful one may be a matter of opinion.• Q: Well, that is a matter of opinion.• That would be a matter of opinion; he had a newspaper which he kept looking at, and shaking out. 