I'm not a very experienced sewer (or quilter). I bought a Pfaff Quilt Expression 4 a couple of months ago and must confess to noticing a big difference even in very day sewing with the IDT. I didn't have the IDT down a for Ten-Minute table runner at Christmas - left up for a special fancy stitch -and could clearly see the difference when I remembered to put it down for the next one.
(The main reason I bought this machine was for the auto presser-foot lift, for pivoting appliqué. I love the way you can set so the foot comes up a smidge automatically, with the needle down. A huge time-saver!)