Maricopa is more of a small, rural community that has become a suburbia town the last few years. Buckeye is a little more connected to the city and with that comes the good and the bad.
Of course the location of the two is very different and might impact your decision based on work etc.
It might be best to spend some time in each, view a few homes in each also just to understand them better. We often tour with buyers to help them understand the areas better, pick a few in each location and compare.
Our goal is to be a true resource for you, an advocate in Phoenix.