The Baptist Church and the Catholic Church are at polar ends since the Baptist church in the United States is an off-shoot of the early Puritan churches, the religion that was a complete break from Catholicism. With the intent to "purify" their church, the Puritans did away with the hierarchy of the Catholic Church which allowed political and religious power; it stripped its churches of stained glass windows, statues, almost all decoration and pagentry. In the Baptist Church there is a lateralism rather than a hierarchy. The congregation selects a minister, and the congregation can fire the minister in contrast to the Roman Catholic priests who are appointed.
The Mass of the Catholic Church is celebrated by only an ordained priest who has a thorough education in theology. The Mass is celebrated each and every Sunday in a certain manner without variation except for high masses which contain more ceremony and pagentry. The greatest difference with this form of worship is in the consecration of the host and the act of transubstantiation: the act of the host and wine becoming the body and blood of Jesus Christ [as Catholics believe]. Through the sacrament of taking Holy Communion, a Catholic can receive grace.
In the Baptist Church, at a Sunday or other service wine cannot even be used as drinking alcholic beverages is strictly forbidden. The communion is simply bread or wafers; there is no consecration, no transubstantiation. Yhe word "fellowship" is often used.
The Baptist service is generally going to be far more participatory, in that you don't just have the priest and the litigant talking or singing, the congregation is often singing hymns or even participating in the service in other ways. You will also likely see many differences in the congregation itself as the demographics of the two religions are extremely different.
I would echo the ideas of Post #3. Catholic Mass is very solemn and very rigid. The same things are said in the same way every time. Only the sermon, for the most part differs from time to time. There is much more ceremony -- the simple fact of being at Mass at going through the actions is seen as a major part of the worship.
Catholic Mass is a ritual whose exact forms are considered to be very important. This is not true of Baptist services.
Aside from the fact that both worship the same God, the two services, and the theology behind them, could not be more different. Catholic Mass reflects the historic worship of the church for over one thousand years and is deeply liturgical. The Eucharist is offered, one kneels at appropriate points in the service, and confession for sins is followed by penance. The Rosary is frequently recited for remission of sins both known and unknown; and prayers are often offered for the dead to spare them the agony of purgatory.
The Baptist Church is based largely on Calvinist theology and has its roots in the American Great Awakening. It is practically devoid of liturgy. Among their theology is the belief that salvation is a one time thing; to use the favorite phrase, "once saved, always saved." The Baptists celebrate Holy Communion, similar to the Eucharist, but it is consumed in the pews. Baptists do not kneel, except to pray. There are no creeds or recitals, other than the Lord's Prayer, and there is no recital of the rosary or confession. Whereas Catholic worship involves a degree of mysticism, this is not true with the Baptists. Baptist ministers typically do not wear robes, whereas Catholic celebrants always do. The Baptists do not pray for the dead, and do not believe in the existence of purgatory.
I think that you can sense a great deal of discussion will be present on this topic. I am not certain if there is one answer. I would like to draw from the President's words on the topic, though. When running for President, then- Senator Obama delivered a speech entitled "A More Perfect Union." The wide ranging and expansive focus of the speech spent some time contrasting the experience of so- called "White" churches and those of so- called "Black" churches. One of the specific lines of mention that helps to bring out the difference in both services is the idea that "... that the most segregated hour in American life occurs on Sunday morning." Indeed, Senator Obama brings up the idea that the experiences of religious services in Catholic Mass and Baptist Services are uniquely different. This difference, he argues, is a critical point where decisions have to be made. Either, one can be content with this difference in expression. Where Baptist services and Catholic mass remains divided in their unique distinct expressions of spirituality. In the speech, Obama points out how Baptist services, such as the ones held at his own Trinity United reveled in intense displays of affection that would sharply contrast with the more refined demonstrations at Catholic mass. Obama challenges reader and listener to either be content with such differences. On the other hand, he suggests that individuals can accept these differences and seek to view them as dynamic, and not static, and seek to understand them and perhaps, overcome their negative propensities. In this, Obama argues that the differences between mass and service can serve as a "teachable moment" on race, spirituality, and American identity. The use of the Framers' of the Constitution line in the Preamble of "In order to form a more perfect union," underscores Obama's idea that while mass and service might be different, it can be a starting point where greater understanding can result. In this light, the difference between both is seen as a valid and divergent expression of political, spiritual, social, and psychological identity. While difference might be present, it does not have to be static, and it can be transformed into a comprhension that helps all to "form a more perfect union."