MUD taxes are going to relate to the initial development of the subdivision as a way for the developer to recover the costs of putting in those roads, utilities, drainage, etc. Regular city taxes will cover schools, road maintenance, city parks, etc. In some areas, particularly in North Texas vs Houston area, the local municipalities are going to charge "impact fees" at permitting to cover many of the costs that are typical in MUDs in Houston area masterplans. Impact fees are part of permitting and can be huge - why you can easily see permits in Frisco cost into the 5 digits, can you can get a permit in some areas of Houston for $1k-$2k, sometimes less.