I tried SITD with a FMQ foot and it was more like drunk driving in the ditch. Blech. Won't do that again.
I have an integrated walking foot on my machine, and one of the feet that came with it is like a foot with a 1/4" guide - but the guide is in the center ... PERFECT for putting it in the ditch and just stitching along!!
When I first started quilting I was quilting straight lines (cross hatching) with a regular foot and boy was it hard. Being a complete newbie (and a self taught one) I related to my dealer how hard that was when I had cause to visit him. He said "why didn't you use the walking foot?" ... the what? Needless to say I purchased one that day and have not turned back. Note: This was on my Husky machine, not the Janome which has the integrated walking foot.