Long arm quilting is way fun! but it's a large investment of money and time so be sure to think everything through.
I would be hesitant to let others rent time on my machine. There may be additional tax and insurance implications. You can't learn on customer quilts. You may be a natural, but most folks need a fair bit of practice before they become profficient. You say that you have the room, but remember that you need at least 2'-3' around the front, back and one side. You will need to get to both sides and the back. will you get lessons from your dealer? Will they come to the house for setup and/or major problems? Most machines are very heavy and difficult to bring in for service. How many other brands have you tried? it's a big investment and you want to make sure that they machine is the right one for you. Quilting for hire is a business, and like any other business you need to do research in your area to make sure that there is need for this service in your area. I would also recommend the book: "Ultimate guide to LA Quilting" by Linda Taylor. She has info on setting up a business.