Although the term "Roman Catholicism" nowadays is seldom intended in a derogatory way, it is not a term that originated in the Catholic Church, nor is it a term that the Church applies to itself, at least in its recent official documents.
The origin of the term "Roman Catholic" seems to have been 16th or 17th-century England, where it was used to distinguish Anglican Christians ("English" Catholics) from Christians in communion with the Bishop of Rome ("Roman" Catholics). In post-Elizabethan England, the term certainly had a derogatory connotation, because Catholics were often seen or portrayed as traitors (since, according to that point of view, they obeyed a foreign monarch). (See the Wikipedia article on this topic.)
Later on, in the 19th Century, the term came to be associated with the so-called Branch Theory. The idea is that the Catholic Church came to be divided in to three great groups, each with an equal claim to descend from the original Catholic, or Universal, Church: the Anglican Church, the Orthodox Church, and (what proponents of the Branch Theory called) the Roman Catholic Church.
Eventually, the term came to be accepted even by Catholics themselves, as a way of emphasizing their loyalty to the Bishop of Rome.
However, the term is misleading in a number of ways: it could lead people to make a false identification between the Western or Latin Church with the Catholic Church, whereas in fact the Catholic Church consists of 23 autonomous Churches of equal dignity, only one of which is the Western Church (albeit the largest in number of members). In those 23 Churches, there is a wide variety of liturgical practice and theological tradition (although all are in communion with the Bishop of Rome and profess the same faith).
Moreover, it could lend credence to the Branch Theory, and in that way undermine the Catholic Church's claim to be the universal Church.
Finally, the "Roman Catholic" Church could be confused with what is properly the Roman Church, that is, the Church or Diocese of Rome itself; such a confusion might give rise to an excessive "Ultramontanism" (an exaggerated opinion of the authority and jurisdiction of the Pope).
For these reasons, official Church documents, at least from Vatican II onward (including the Catechism of the Catholic Church) avoid the term "Roman Catholic" entirely.
I think it would, therefore, be appropriate to follow suit. Not everyone accepts the claim of the Catholic Church to be the universal Church, just as not everyone accepts the claim of the Orthodox Churches, say, to have all the right doctrine (orthodoxia), but it seems a token of respect to use the name preferred by the church in question.