I bought my 830 new.. I have sewn around the world on it sevearl times.. That machine has never skipped a beat.. It's a gem.. I'll keep it until the day I die!
Consider this: The Bernina 830 is such a well known, well recieved machine, one that has such a wonderful reputation that Bernina has come out with a new "830" version just last year.. The ONLY reason a company would do that is because they know the popularity of their old 830 and are hoping this new 830 will enjoy a sales boost from the reputation.. I'd hang on to that machine if I were you!!