Some people are comfortable with the word "God", some are not. Some find the word "God" to be limiting, lacking the enormity of this wonderful source of life and beauty around us. Michael actually prefers not to use the word "God;" using the Eastern term "Tao," instead (pronounced DOW but with a hard "D", like TDOW; meaning: the way).
Michael has explained that we (especially those of the European Culture, or Western Civilization) have turned the word "God" into something far from what is true on a universal level. To help us move away from the stereotypes and limited images of "God," Michael uses the term "Tao," which brings with it no preconceived limitations or personifications.
You may use whatever term you personally prefer. Michael, nor any Michael Students or Channels, have any rules about this in any way. Just remember that when Michael speaks of "Tao", they are referring to the general, unlimited energy that others may call "The Universe," or "Love," or "God," or "All-That-Is."
Regardless of the name, most people seem to have some form of recognition of a higher source of which we are all a part and in which we all reside. Michael's teachings supports the concept that this source does exist in some way.