Find out if the 440 will accomodate the stitch regulator. I can't remember if it does. It it is the 440QE that takes the stitch regulator, then find out how much that machine is. Maybe you could swing that machine. That would be the deciding factor for me. That alone would make free motion quilting or free motion embroidery much easier. I have a Viking Desiginer 1 and enjoy it, but would love to have the Bernina 820 with the built in stitch regulator and big throat space.
My suggestion is to really test drive both machines before you buy. Oh, and I got two emails about a big sale Viking is having. Demo machines for half price. I remember the Diamond was 50% off. This is through the Viking Sewing Gallery stores in Joannes in Plano and Frisco, TX.You might be able to get something a little better.
I'm not familiar with the Sapphire, but I do like the Viking machines. Good luck with your decision making.