My son is returning tomorrow night from a two year LDS mission to El Salvador. My husband and I both served missions when we were young, and we both feel, as most returned missionaries feel, that it was the best 2 years, or in my case 18 months. (Women serve only 18 months.) That isn't to say that the time is easy, or that it is always happy. Just like normal life, there are ups and downs, happy times, and trials. But when you come home, and then have a lifetime to look back at those short years of service, it really is some of the fondest memories of your life.
My son has really enjoyed his time, as has my daughter who will be returning the end of this month. She is serving in Taiwan. They both really have grown through the experience, and I have seen many ways in which they have changed. Some years ago we paid a substantial amount of money for my daughter to spend the summer in a study abroad program in Jerusalem. She learned about the religions of the area, as well as the history. She visited many religious sites, and had many wonderful experiences. But I think she will agree that her time as a missionary has been far more meaningful. YOu just can't buy those kinds of experiences.
I'm so thankful my children could be missionaries. In our church, many people believe that when you have children serving missions that your family is blessed because of it. Somehow they think that maybe we would be blessed financially. Missions are volunteer, and missionaries and their families pay the way. THey aren't paid for their service. We have been blessed that some of our family members have helped to support our missionaries. So yes, we have been blessed. But honestly, the best blessing our family has received from our two children serving missions is that they got to serve a mission! Their whole lives will be changed because of this experience. Their children's lives will also be influenced because of their parents' experiences which they will share. This is the kind of education that you can't find in a college. It really is the best two years.