I have 2 2100 series Pfaffs. I have insomnia at times and would sew in the middle of the night. The middle of the night is when Murphy's law kicks in and you can't do anything about it. I'd just use the other machine. If it happened to be embroidery, I could just change whatever component caused the problem and pick up the last stitch.
Serger and cover stitch. Didn't like the wide foot on the combo machine.
Brother 1500 - Better straight stitch and larger harp for FMQ. The Pfaff will do it, but the noise of the presser foot drives me crazy. If you use the knee lift, the presser foot will go ah-ah-ah on lifting. I'm glad the 1500 doesn't make noises like beeps, bells and warnings.