After reading about sergers on Pattern Review.com, I ordered a Brother 1034 serger online about five years ago just to try one out for general sewing. It cost somewhere between $100 and $125. It is still working fine, no service needed at all.
About the only thing I use it for is overcasting raw edges on woven fabrics for pants and some shirts. I thought that I would use the three thread stretch stitch for knit tops, but I still like a narrow zig zag the best.
I serged the edge on a quilt until I could find a binding fabric that I liked. I needed to use the quilt, so here it is two years later and I still have a serged edge! I think there is a method for quilting with a serger, but I would think you would end up with bulky seams.
Oh, and I don't mind the threading--- my other machines are vintage, so I don't know what I'm missing.