I'm sure there are a lot of us that have been in the same place. I decided to buy a CAT mini-excavator a few years back and have been happy with that decision. It's mine, I know the history and service, and it's there when I want it. Part of my calculus is that I have almost never rented a piece of equipment that actually worked right. Something was always wrong with it. In fact, I'm so satisfied with the CAT buy that I just added a D3 dozer to the herd. And, like every tool you've ever bought, you find new and unexpected uses for it.
I vote to own.