I walked into my local sew store, asked the owner to educate me on sergers, what they were good for, what they did and how they worked. She spent 2 HOURS with me, even teaching me the basics of how to thread/sew. They happened to have a beautiful self-threading Babylock Evolve (8 thread machine, Cover and Serge) just come in on a trade in. The owner showed me the difference between 4 thread models and the big one. She in fact did NOT try to sell me the big one, but recommended the 4 thread for me (a beginner serger). I left the shop, an hour after closing time having put a 'hold' on the Evolve. I bought it the next morning and spent that day at the shop having a one on one training session with the shop's serging instructor. I left, tired... but knowledgeable and confident. (and much poorer!).
It's been 6 months and I've used the serger to:
repair or make towels,
cover stitch knit t-shirts,
make curtains for my sew room,
serged pin tuck doll dresses,
ruffles for pillows,
cushions and canvas covers for my bar stools,
finished seams on garments,
cool handle & pocketed book bags made out of upholstery samples and home dec fabric swatches,
a quilted Thinsilate Lunch Tote, with inside pockets for those plastic Ice bricks, plastic silverware, and tupperware,
an easy/quick quilted thanksgiving wall hanging (ohio stars),
rolled edge linen napkins to match,
a pretty silk scarf (rolled edge again),
Sunbrella boat cushion covers,
nylon ripstop fabric 'flags' for the flag pole out front,
mending and reshaping my DH's golf and work shirts,
and prob. much more that I don't even remember.
A serger can do many things, piping, cording, felling, rolled edge, hemming, blind hemming, flatlocking, pin tucking, gathering, elastic gathering, beading, decorative stitches, etc. It can even do multiple things, at the same time and cut the fabric for you too. I still use my sewing machine for lots, but I turn back and forth between the two all the time now.
Okay... so all the above is to say... you will only use your serger - if you get training on it, and it's fun and not frustrating to use.
That big babylock of mine has up to 8 threads and 5 needles! - but it's self threading using air puffs. When I do a big combo stitch requiring 6 or more threads... it would be HORRIFIC if I couldn't thread it fast. (It takes me about 5 minutes tops to thread even the most complicated cover or cover/serge combo stitches. That makes me happy!)
Most people seem to get frustrated with their sergers cause they take so long to thread, the machine is fussy/keeps jamming or the threads get tangled or whatever. So do yourself a favor, and buy a self threading serger. Even if it's a lot more $$$. You will actually USE the machine versus having it collect expensive dust bunnies....
Also... get it from a good dealer or pay to take it in and have classes on it. Classes on YOUR machine. Then use it. Explore it, try new things... just for the coolness of it.
Oh! To the lady that did the quilt with WAVE stitches on the outside... try using that stitch on the outside of pocketbook style bags joining sumptuous upholstery fabrics with velvets or thick silks or other various types of home deck stuff. It's stunning!
As you can tell, I'm having fun with my Evolve!