The machine seems solid enough for my purposes. I can see why sergers are intimidating for people: they're real mechanical contraptions, with stuff going in six different directions at once. Still, I had little trouble getting it set up and threaded, and the printed instructions are clear enough that I was able to make properly tensioned 4-thread seams in no time. I tried making a rolled hem seam, but the fabric didn't roll; I suspect that really only works with light fabrics, depending as it does on the thread to roll the fabric over.
I've ordered a bunch of thread (wooly nylon for the loopers, at Stacey Leigh's recommendation, and cotton for the needles), and will be playing with sewing some spare scraps of nylon and cotton spandex when it arrives.