Agree with others that when you pick up you machine you have a demo. However, IMHO it is more important that you do it in front of the technician a few times, to make sure you are doing it right. While we "think" we have observed correctly and know how, doing it a few times proves the point and lets him/her check that we are doing it correctly. Or give us tips to not create problems in the future.
The auto-threader can easily be bent ... it's just a fine wire. Believe me, I know! Another thing that I found with my 6600, it was best to put the needle in the default position. Yes, it is supposed to work fine if it has been moved, but I did find it made a difference.
For the auto-cutter ... I found that I had to be patient! In this world of instant, fast is not fast enough!!!
Sloooow down, take a breath and let the machine finish it's process of cutting the thread ... you can hear it. Yes, I was frustrated too ... then once I learned that, it made a difference. And if you think that time delay seems like eons ... try the Bernina 820 (that I have now) .... it seems like longer than eons!