I exchanged the one that was totally non-functional and got another one. I can't say that fixed the issues, but this one works better.
One thing I discovered is that the little plastic guard behind the thread tension knob is NOT your friend. (It seems to be there to keep you from over-tensing the thread.) With my machine, I have to tense the thread WAY more than it allows. I basically just kept turning the knob until the guard bent down. You've literally got to turn that thing almost as far as it will go. (If the thread breaks, you've gone too far!)
Another thing is that I searched everything with an adapter in my house until I found one with specs similar to the ones imprinted on the adapter plug on the machine and which fit the plug. Huge difference when compared to batteries. A lot more power. It really should come with an adapter. (The only problem is that the power surge blew the machine's light.)
I managed to sew a Gothic/Victorian backpack with the thing, and I took it to Disneyland. That was in October, and it's still in one piece, so ultimately I did get functionality out of it.