I have a Sapphire 830--the bottom model. I love it! It sews like a workhorse, it has the needle down option, which, when you stop stitching, the needle is down but the foot is up about 1/8"--enough to allow you to slip the next piece of fabric under the foot. It has a good number of stitches--and this is where I wish I had a higher version--for more stitches. I have never used a machine that had the automatic thread cutter nor does my model have the almost empty bobbin warning beep--but it's pretty easy to see through the bobbin plate to see how full the bobbin is. My machine was a gift to me--so I can't kick the gift horse in the mouth, but I really love my machine. If I could choose, I would get the top of the line model . . . One great thing about the Sapphire is that it has a 14" throat--which gives you more room for the quilt.
Viking now has the Diamond machine, which is a golly-gee-whiz machine with everything you could ever want.