I have a Majestic 10 foot frame with a Baby Lock Crown Jewel which is an 18inch longarm. The frame is great - very sturdy. It does not shake at all and I love the rails system. I am sure I could use it with a domestic machine, but would need a carriage to put it on. Candace is right about the small opening. When you get to the bottom of the quilt and most of the quilt is rolled up on the take up rail, it may be 5 or 6 inches in width on the rail. With my Bernina, that would only leave me 1 1/2 to 2 12 inches of quilting room.
Good luck with your endeaver.
When I bought my system, Baby Lock was offering no interest loans.