"....maybe what its like in this line of work compared to other mechanical engineering disciplines...."
As far as for anyone being able to tell you what it is like compared to other mechanical engineering disciplines it is tough to compare. The vast majority of engineers do work that is no where related to what they were trained for in school. It is what you make out of it.
If you like to do projects, go through the cycle from determining the client's needs, design it on paper and see it get built and working the way it should work and at the end of the day get satisfaction out of a job well done you might want to consider it as a career. But if you find out that you don't like it, you are not tied to it for the rest of your life. Just get into another field. You will have gained valuable experience technically, how projects are managed, the roles that individual people play etc. You will have seen complainers and performers, poeple who are driven to move ahead in a company and people who are steady workers but don't want the responsibility and as such do not want to move ahead. You will see the managing of people aspect and you will also see the aspect of how people go about to win projects. Your eyes will have opened a little wider about the real world. What i just said above is applicable to every job in any field. Any succeeding company that you work for will gain the benefit of that experience.