I would stay away from an new Bernina....lots of trouble with them. They are NOT the company they used to be. And even when the problems are minor they require a trip back to the dealer/tech. I had to find a new tech because the one where I bought the machine was unable/unwilling to fix the problem. So now I drive 1 1/2 hour each way fir even a simple adjustment.
Some parts on the new 700 series machines are so fragile they they break in normal usage. The threader, for example, and the company calls that "wear and tear" and charged $107 for the part.
Whatever brand you choose be sure that the service is close and competent. IMHO, Janome is the most reliable, but I'm sure some will have differing opinions.