It's really a variety of things, the one that bothers me the most is that the Accufeed foot looks crooked when I'm using it. It has caused me more than once to not have an accurate SITD and this week I finally hit the wall. After a year of using it, I'm just not bonding with it, and the idiosyncrasies make me want to lose my mind. It's finicky about thread (I'm sorry but if you have to change the type as well as the size of needle to find one that will work to make a regular seam, that's finicky to me) - it was suggested I try various sizes and types of needles to find one that would work with Aurifil ... Ummm ... no. Sometimes it makes knocking noises.
And one that just really doesn't make sense to me - the machine comes with both a 1/4" foot AND a straight stitch needle plate, but you cannot use them together, because the 1/4" foot requires the needle to be moved to the right. What's the point of the straight stitch needle plate for quilting if you can't use it for piecing as well as FMQ?
Some folks on the Yahoo group suggested there was a problem with my dealer, but that isn't the case. I really like my dealer and they've tried to help me, but the machine is just not a good fit for me. I'm not kidding when I say that the 11" throat is the best thing about the machine ... I don't even like the stitch quality ... My 15 yr old Viking does a much more beautiful stitch!