I have a QDII and love it. The choice was between the QDII and the first Bernina to have the stitch regulator. The folks selling the Bernina were so rude and full of themselves, after just demonstrating it at a quilt show, that I bought the Viking.
There have been times when I've wished there had been another Bernina dealer to go with, as I don't fmq very well, but the viking has been a wonderful choice. I don't have the embroidery unit and never have missed it. The D cards are very hard to get, however. Does the machine you're looking at come with some? Also, the QDII was made in Sweden, which should help its value.
hugs,
Charlotte