I bought my second Brother embroidery machine from a demonstrator in 2004. It has served me well, though I only use it for normal sewing as I have a couple of later model machines for embroidery. The stitch count works out about 27,000 per week, and given that many designs have 5 - 10,000 stitches and the machine is 5 yrs old, that's not bad.
Is the dealer or seller prepared to give you a decent guarantee and take responsibility if it turns out to be a lemon?, if so it should be a good deal, and I would insist on some free lessons as well. At least the dealer should know if there were any issues with it. Good luck