I have a Pfaff expression 2.0, which, of course, is a different model, but I love mine. I bought a machine that wasn't really used, but it had been a demonstrator in the shop. I actually thought that was okay, that if it had been working for others interested in buying, it would work for me.
I have had it a year. I have had no problems, and I sew quite a bit.
If I were you, I would spend a lot of time with the machine. See if it will do everything you want it to, and look at the owner's manual very carefully. My manual is very well written, and I use it any time I can't remember how to do something....even threading the machine or doing a button hole.
My Pfaff dealer works on machines that he hasn't sold. The only real advantage that I have from buying my machine there is that if I need to take it in, he has told me he would do mine before he would work on one he had not sold....something about warranty, I think. I don't know what his prices are for service, so I can't help there. Well, I did get 12 free lessons, but I only went to 4. I just felt like I already knew enough after those four lessons.
Do you have a Pfaff dealer in the area? That might make a difference too.
I can tell you that I have a friend who traded in her Pfaff for a fancier model after only having it two months. Anyone getting her machine would certainly be getting their money's worth. I think she went from an expression . 2.0 to an expression 4.0.