I bought a used BabyLoc serger from a friend (he "recovers" items from Yard Sales) OILED oiled oiled, it still sewed a very balanced stitch. Threading was miserable, because my fingers are too big for space, finally got a tool that "helps" thread, BUT worked like crazy for 30 minutes, then the feed dogs would sieze up. Research, this is a known issue, and is not easily fixed. Friend sold it on eBay for parts. Used that money to buy a BRAND NEW Brother 1043D. LOVE it! Easy to thread, lots of options, and came with the Ruffler foot and Differential feed feed dogs. My DD is having a girl next month, and this is one baby who will wear ruffles. and pillows will have ruffles. I just need to have it on a "solid" table. The serger has a lot more motion than my sewing machines! (FAST!) I love it and am so glad. This opens a whole new way to use shiny threads for decoration. And I could see doing a "reverse seam" quilt, especially with some of the cool quilting variegated threads out there!
My advice, try them out first. find a friend who has one, check at fabric shop, take or buy some material you don't mind testing. Have them show you the threading, and if you do buy one, READ the book, watch the video's and KEEP the book where you can get to it at all times! LOL, I've learned that one the hard way. put it all away, neat and tidy. NOT. Sergers are not just for knit clothes anymore!