I have a Brother Pacesetter NX600 machine and LOVE it!!
Best features for me are the automatic needle threader, needle up/down, and kneelift. Also love the on/off button vs having to use the foot pedal. I was going to say I have had it for 4 years now but just looked at the warranty and see that I bought it in Jan 2005 !!! How time flies....it was a birthday gift from DH....I have never had a problem with it. (hope I don't jinx it now) I only wish it had a larger space to the right of the needle for quilting larger items....