Superlate,
Welcome to the pressure washing business and the board. As a startup, you will find the info in the boards archives very usefull for quick answers. The search engine will become your friend. The members here are a great bunch of people with a vast amount of knowledge and experience to share.
Surface Cleaners:
If you are going to be doing flatwork, a surface cleaner is one of the best time saving tools you can invest in, as long as your machine has the capacity to drive it as Tim mentioned. They are not diffficult to operate. One word of warning, while it is running, keep it moving. If you let it set in one spot for more than a couple of seconds it can(on some concrete) erode a nice circle on the surface of the concrete. Play with it at home a bit first to get the hang of it. Of course if you lived in Salt Lake that might not be a bad thing, you might be able to get some jobs permanently etching the olympic rings on concrete.
Good luck,