I agree, I found a huge difference between the Bernina I would use in class and come home to my Kenmore and it was like night and day.
I talked with DH and the ladies that buy and sell the Bernina's at my LQS. It was a lot of money either way but Wendy and the Shop Owner explained all the differences between the units. So we ended up going with the Bernina 550. The shop has a 10 month Bernina class that meets once a month and they teach you to do small and large projects using the various tools available on the machine. They did this because Wendy (Bernina Rep) said when she bought her's she didn't know how to use everything and didn't want to see new customers in the same boat. I'm very happy with my machine and DH has peace and quiet instead of hearing me yelling at the old machine.