I have lived in both towns. Franklin is smaller and has more money. It is a nice town and does have a huge mall. It is pricey so check out the price of homes. M'boro is a larger town with a small town feel. My husband and I both went to college here and love it. There is more crime all the time as is everywhere. M'boro has many new neighborhoods and is growing rapidly. We also have a new outdoor mall called The Ave. We have tons of restaurants and more keep coming b/c of how fast it is growing. M'boro has more to do in general but Franklin is not lacking. They both have things for kids to do. If you can afford Franklin, consider Brentwood right up the road. It is even smaller and has even more money, town is really pretty. Small and not much to do though. Both towns have really good schools. Rutherford County (M'boro) has some top schools and also has Magnet schools and several private that are affordable. You can look online at the grades each school is given. Franklin is Williamson County and has top schools as well. I think Rutherford and Williamson County have the top schools in TN. so both are good choices. Franklin has the top private schools over M'boro but are very pricey. M'boro is a college town but is so big now that unless you are near or around the college, you don't really run into the student life. Personally, Franklin is prettier to me but M'boro is more full of life.
Great choices, don't think you can go wrong. You could consider getting an apt for 6 mos to see which you prefer or ask at your husband's job what they think. both are close to downtown, one is off 24 and Franklin is off 65. About the same distance.