I quilted 4 quilts on my domestic machine. The last one I did was about 60 x 60 and I cussed a lot! I saw the sit down sweet 16 and I bought it. It doesn't take up the huge space a long arms does, yet I can work on big quilts easily. My FMQ improved because I could concentrate on quilting rather than continually repositioning my quilt. The table isn't that big, but for large quilts you will probably want to add some surface area to the sides. Lots of people make do with ironing boards or $30 tables from the big box stores. I tried long arms, but I prefer the tactile feel of the fabric under my hands rather than handles - YMMV.
Pam