If you can afford the self-threading ones, get one of those because machines of that quality are going to be quieter and nicer to work with.
I have the Brother 1034D and it's been working great for about 3 years. VERY easy to thread - next best thing to self-threading. Switching to narrow rolled hem or back to normal serging takes about 10 seconds.
But it *is* noisy. I just live with it because I love it so much. But, when it breaks, I'll look at the air-threading sergers and see if I can afford one of those. If not, I'd definitely buy this model again.
