I haven't used a frame, only seen them at quilt shows. I think it would work fine, and the beauty is that you can use your own machine. However, it wouldn't be foolproof-- you still have to learn to manipulate the quilt to get the effect you want. I tried an embroidery frame once at the suggestion of a friend, but it didn't suit me. The area that you can work at one time is very limited, so you're constantly having to re-position the hoop.
For your king sized quilt, I strongly suggest you look at one of the methods for doing it in sections. That really has helped me to do the large ones without just wearing out. and I find that the section is of a size that I can quilt the design I want rather than just what I can do with the huge bulk (if you understand what I'm trying tosay). Get a book, go to the library, before you do the quilt to see if it will work for you.