This specific question always comes from Protestants because open-minded Catholics will look at a Christian Wicca Sabbat and say, "this is very much like a mass"! Actually, there is a very sound reason for that: Christianity spread worldwide via the Roman Catholic Church.
Their tactic for converting Paganism into Christianity was to make the rituals of Pagans into masses, make each set of Pagan Deities into Saints, in exchange for taking on the Christian Triune God; those opposed or those who did not conform were killed. The Sword or the Lord, it's your choice. This method of absorbing the earth-based religions was a very simple but highly effective plan.
If you are a Protestant, you must remember that you are a split-off of the Roman Catholic Church. You are the religious affiliation that protested the Roman Catholic Church. If you are a Roman Catholic, then all your masses and ceremonies are based on or stolen directly from the Pagan religions.
Another reason it may seem unfamiliar is because the average Christian church service is lead by a single minister or priest and the congregation is generally passive. Here is a good time to speak out on behalf of the “hands-on” benefits of personal spiritual participation involved in Wicca. This aspect allows each individual to be their own minister and to be their own congregation at the same time.
Each person is a priest and each person is a priestess. In Wicca, each practitioner can have a part to play in the worship service. Whether you practice Wicca alone as a solitary or worship with a group, the assembling of the ceremony is part of the learning experience. Once parts are established and assigned, then the practitioner has to “do his/her homework” to be prepared for the ritual.
This tends to enhance your knowledge of the ceremony, cause heartfelt emotions toward the rite being conducted, and as a result, deepen each practitioner's connection to the Divine.
Practitioners gain so much more spiritually by getting involved with the entire Circle of Worship than by merely listening to another person recites passages from a book. Regarding this aspect of methods of worship, we can compare the Organized Church to going to college, at some point, you have to put down the books and begin to put your education into use.
No one can make a living being only a professional college student! Would you trust a surgeon to operate on you if she/he has only studied the human body from a textbook? Wicca encourages the Christian to take the lessons of the Bible, put them into action and to write their own ceremonies.