A few months ago I purchased the Bernina stitch-in-the-ditch foot. I didn't even know about it but I came across someone suggesting it for machine binding. It took me awhile to locate one as every Bernina dealer was sold out and the item was on backorder. I received mine after about a 5 or 6 week wait.
I finally got to use it today. It is amazing. I read some mixed reviews on the Yahoo Bernina group but I have no reservations whatsoever. The blade on the foot opens up the seam and just lays the stitches right in, well, the ditch.
For this quilt I spray basted it (on my bed for the first time, no problems) started my stabilizing stitches around the inside of the border. When I was done I could barely see the stitching. I tried to get a picture of it. The stitching on the horizontal border is as close to perfect as I have ever come. It took me one side to get the hang of it but once I did it was super easy and much faster because I didn't have to keep stopping and starting and making sure I was holding the seam open, the foot does it for you.
As an aside - this is also my first time using Hobbs wool batting. I like it. Already with the stitching around the perimeter of the quilt and then the grid inside it has a nice fullness, just shy of puffiness. I can't wait until this one is done and washed.