I know that there are people out there that LOVE their sergers, but I'm certainly not one of them. About 8, or 9 years ago, I bought 2 different styles of machines for our swimwear business, a JUKI and a JANOME. We used them to make first samples and then sent the samples to the pros for refinement. It would take hours to thread them and get them running and then they constantly went out of whack. What a nightmare! When I asked my sewing contractor how he managed with his professional sergers, he said the same thing. He spent all day going from table to table, fixing his machines. It was a full time job just keeping them running. It's a surprise that any garments ever got to the retailers.
Honestly, I'd seriously rethink the serger purchase, unless you really have a need for that kind of seam finishing, or you work with stretch fabrics a lot.
And that's my 2 cents.
~ Cindy