The Dallas and Fort Worth metro areas are quite unique compared to most other cities in the United States; due to the size and continuous expansion of both cities the metro areas eventually became a single city somewhat. This is exactly where the Mid Cities area of Dallas and Fort Worth comes into the picture, Mid Cities is the area immediately between the two cities. Obviously the location has also made Mid Cities a very popular location since it is located directly in the middle of everything.
Most of the Mid Cities area is suburban and heavily residential which makes it a very popular area for people that wish to live outside of either of the nearby cities. Mid Cities is technically made up of multiple cities and neighborhoods but nearly all of them are suburban residential developments that are home to people that work in either Dallas or Fort Worth. Because the Mid Cities area is so popular there is obviously plenty of necessary amenities found within the area as well; there are multiple shopping and entertainment districts scattered all throughout the area which means there is always something close by no matter where you're at in the Mid Cities.
Of course the most important and most popular thing about the Mid Cities is the convenient access to downtown Dallas and Fort Worth. Regardless of which city you want to commute to there are multiple highways and transportation systems that offer quick, easy, and convenient access to the cities. The Mid Cities area was essentially built around the idea of commuting to either Dallas or Fort Worth so it only makes sense that it would be well designed for commuters. Overall Mid Cities is just a great place to live if you want to get out of the city while still being close enough to conveniently and quickly make it to work. Dallas and Fort Worth are both just a short drive away from any part of the Mid Cities area which means it really is the most convenient and most centrally located city or neighborhood in the area. If you want to be closer to the city and downtown life then obviously there are better options available but in most ways the Mid Cities part of Dallas and Fort Worth is one of the most popular and most convenient areas available.