I have had a Babylock machine for 13 years now. It was a high school graduation gift! It is a PAIN to thread, and when one thread breaks (which they do from time to time...) you have to UNTHREAD and then RETHREAD the entire thing from scratch!

I wish that it was easier to thread. I am sure that the newer models (even the ones without the jet air threading...) are easier than the old models. Aside from the threading issue, I have NEVER had any problems with this machine. I love it, and it was easy to learn to use. I agree with the above posters, that you should buy from a reputable source. ALSO, look for a dealer with a trade-in program. Sometimes if you buy a machine, and then change your mind or want to upgrade within the year, you can get the entire original purchase price of your machine towards a totally new one!
Either way you go, there will be a learning period, but a serger is really a great way to get that professional look on your work. I find it great for children's clothes so that they last longer, and are less likely to fray or have irritating seams for their sensitive skin.
Good Luck!