I think long arm machines are a true luxury, an investment with no return for your money...unless, of course, you quilt for others. But I have seen many long arms up for sale by quilters who got so busy quilting for everyone else that they no longer had the enjoyment of planning, piecing, quilting, and finishing personal projects.
If money were no object, and I could justify it on my conscience, I would definitely have one. But then I would need to buy a bigger house or at least add on to our existing house to make room for the frame!
No, I feel it is more important to put funds aside for daughter's college and our retirement. With practice, I can do a fine job quilting on my regular machine.