I have echo quilted with feed dogs up using a walking foot. Where the curves are tight, it involves a lot of stopping to re-position the quilt sandwich, but at the time that was a small price for me to pay in order to avoid free motion quilting (and the uneven stitches I was getting). Someone who is good at FMQ would prefer to do it that way. If it's a beginner, though, and they are particular about stitch length, the way I did it make it very easy to get both even stitches and even distances between the lines of stitching.