I can't answer your question about this Necchi in particular as I don't own one (yet:>). If you don't get your answer here, there's a vintage Necchi group on yahoo that I'm sure can help you. I agree that finding a machine that's a good FMQer is important. Some machines are simply better at it than others and the 401 and 500 machines are not good machines for it. Yes, the horizontal bobbin system is preferred by many for FMQing as lots of people(myself included) think the tension is better and stitch quality is better.
Have you shopped around for a Singer 301 or 15?
Powerful and fast is a good thing for me since I sew and FMQ like a speed demon:>