I have the Pfaff Expression2 and I love it. I have only had it since xmas, and it's done a lot of hard work for the time I've had it, (not just quilting).
Like yourself I wanted a Bernina at the time, simply because that's what I had for the past 30 years, but the $$ was out of my reach, so I settled for the Pfaff.
It did take some getting used too, and I had problems with cotton breaking, and fabric getting caught up, though once I had the lessons, that was part of the deal it was smooth sailing and I haven't looked back.
I think all machines are quite different, and it's a matter of getting to know your machine, and how to use it. I really don't think you have made a bad decission at all. Actually I would have got the Expression4 if I had of had the $$.
Good luck with your choice. :-D