I use the Brother LS-1520. It was a $99 machine, but it does the job. I've had it for about..9 years, I believe? But it still works just as well as it did new. I've never had it serviced, just have cleaned/oiled it a few times. Though it could probably use a tension adjustment eventually. After sewing for long periods of time in one sitting, the tension can kind of go out of wack. But I believe that's true for many machines. (As lead to believe by those ladies I had to fill out the servicing paperwork for while I used to work at a fabric store.) But other than holding up well, it's also an easy machine to use. I mean, I was about 10 when I first got it.
Brother has since come out with newer versions, but I would trust they would have the same quality. Many of which are still within the the prices of $90-$140.
I'm actually thinking about buying a Brother serger in the near-ish future. ^^