Sergers create the type of loopy finish you usually see on the seams of commercially made garments. By using two, three or four threads, sergers create an overlock stitch that keeps edges of fabric from fraying and rolling. They can also be used to stitch and finish a seam all at once and are particularly useful for stretchy fabrics, since serger stitches are able to stretch with a garment. In addition to finishing seams, many people also use sergers to create ruffles, sew elastic and create overcast rolled hems -- a decorative finish that's nice for lingerie and for ruffles on dresses. Sergers cannot, however, be used to topstitch, to put in a zipper or to make buttonholes, so a serger can't replace a regular sewing machine entirely.
If your main need is finishing seam allowances plus the occasional rolled hem, a basic serger is all you need. You can find some budget sergers at Walmart.com, Amazon.com or JoAnn.com; prices start at $200. While there aren't many reviews in general for sergers, we found more than 500 owner-written reviews for the Brother 1034D (*Est. $250), a basic 2/3/4-thread serger. All sergers in this price range (in fact, all sergers that cost less than about $1,000) must be threaded manually. While owners say that manually threading a serger is never much fun, the Brother 1034D does include color-coded thread guides and an instructional CD to make it easier. Another bonus is that this serger comes pre-threaded, so you can study how the threading works before trying it yourself. The overwhelming majority of owners say the Brother 1034D is a great serger, but several note that it's loud and vibrates quite a bit.
You can find sergers with automatic threading, but they tend to be expensive. Baby Lock is the most respected name in sewing forums, and models that include the company's Jet Air threading features get glowing raves. This auto-threading feature eliminates the hassle of manually maneuvering each thread through its guides by using air to push the thread through the machine. The Baby Lock Eclipse DX (*Est. $900) is the company's cheapest machine with Jet Air, but otherwise, it's still a 2/3/4-thread serger, performing the same functions as less expensive machines. Baby Lock sergers and sewing machines are available only through specialty dealers.
Lastly, some high-end sergers can also coverstitch -- a type of stitch used on stretchy fabrics to make them appear to be topstitched, but without compromising the elasticity of the fabric. This type of stitch is especially handy for sewing workout clothes, dance costumes and swimwear. In our research, we found quite a few owners that were disappointed to find that their 2/3/4-thread serger could not coverstitch. You need at least five threads to coverstitch and even then, not all five-thread sergers have a coverstitch feature. Sergers that include a coverstitch start at about $1,000, with most in the $1,500 to $2,000 range.
An exception is the Juki MO-735 (*Est. $1,100), which is just about the least expensive coverstitch-capable serger we found. Furthermore, the owner reviews we found for this serger are excellent; owners say it's well built and sturdy, and the beautiful rolled-hem function is particularly praised. Owners say that it takes some time to switch to coverstitching, but that it's not difficult, and all say this stitch works very well.
In summary, if you're like 90 percent of stitchers who merely want an inexpensive serger for finishing the insides of seams, the Brother 1034D gets the most feedback. If you're running a small business or can spend more for convenience features, the Baby Lock and Juki sergers are good bets.
We found helpful buyer's guides for serger sewing machines at About.com and Sewing.org, but actual serger reviews are few and far between with a few exceptions. We did find plenty of user reviews for inexpensive sergers sold at Walmart.com, JoAnn.com and Amazon.com. As for more expensive sergers, we found great user feedback at PatternReview.com, though navigation is a pain. We also found some helpful comments on the best sergers at sewing forums, including GardenWeb.com.