The 630 is geared as much to quilters as the 440, it just has more features. The machines that are better for quilters are the 5.5mm machines with the optional BSR foot. In the Bernina line up, those would include the 430/440 Auroras, and the 630/635 Artistas. The 430/440/450(9mm) are being replaced this month with the 500 series, which will be announced at Bernina University this month... nothing known about them yet.
The newer 820 is also portrayed as a quilter's machine, but I personally don't like piecing on a 9mm feed dog machine. Having owned the 440, the 630, the 730 and the new 830, I think the 430/440 are terrific for quilters, and the 630/635 if you want to embroider as well.