There are pros and cons to each. Some people find that having more people in the call is motivating, while others find the deeper camaraderie of a smaller call more motivational. There is less individual attention given in big groups, which is ideal for busy people who require just a quick check-in. Some people prefer to sit in and benefit silently from the recovery atmosphere, while not actively participating themselves. In this case, big groups are a better option. The choice between big or small groups is up to you and the experience that you want to have.