I'm a garment sewer who also quilts, and I LOVE my serger. But the only quilting thing I've used it for is serging my fabric ends before prewashing. Otherwise, it's great for sewing knits and for finishing seams.
I have a Necchi, and it's been working great for me since I bought it six years ago. If possible, get a serger from a local fabric store which teaches classes on how to use it. I bought mine following an intro to serging class. I haven't used half the stuff I learned, but it was great to get the exposure.