I have the Brother PR 620 and love it. It has the 6 threads and is pretty user friendly especially if you are already familiar with machine embroidery. They have the 650 out now I believe.
Babylock has one at the shop I do volunteer quilting at and it is very similar to the Brother and I have heard a lot of good things about it as well. I have a couple of babylock machines and haven't had any issues with them.