CPS is an SI business automation tool built on File maker Pro. Great system for estimating, work orders and basic CRM features specifically designed for our industry. They have a drawing tool but I have never used it myself. When I used CPS, the company I worked for did not have the drawing feature enabled. If you are using Excel, Word, QuickBooks or something like that mix then you would definitely benefit from a business automation tool like CPS.
There are others that are pretty good as well.