It is very commonly used to analyze antenna structures and a number of different applications. It continues to be very popular, probably the most popular modeling technique used in electromagnetics. The MoM technique is a frequency domain technique. It will only analyze a single frequency at a time, although most popular software codes allow the solution to iterate over a number of frequencies. Once these currents are known, then the E field at any point in space is determined from the sum of all the contributions from all the wire segments and surface patches.
Every modeling technique has some strengths and some weaknesses.
MoM is a very versatile modeling technique. It is also a very intuitive technique, so users can easily understand how to use it, and know what to expect from a given model. MoM models only the metal structure, and not the space around it. Since MoM is a frequency domain technique, it can solve problems very quickly, if only one frequency is desired. If multiple frequencies are desired, then the simulation will take longer, but still solutions are often available is a short amount of time.