You know I tried that flat-fell foot (after reading your book as it happens) and I just could't work with it. It's possible I just didn't persevere enough. They're a real nuisance to feed into.
I'm surprised to hear that, but it's not an unusual response, I guess. I've certainly heard and read lots of comments about how folks don't like them or think they're not justified. It always seems, though, if I have a chance to look more closely at what they're doing, that they're using the ¼-in or 8mm foot, and wanting to make that wide a stitch...which is perfectly easy to do without a foot, and as I said above, doesn't often feed as smoothly, unless the fabric is heavier as well.
Were you using a 4mm/ ⅛-in foot/seam? I find them quite simple to load up and since they're only folding, not rolling, much easier to manage than rolled hemmers. But I WAS motivated; I was certain I'd found the Holy Grail of my how-to-make-a-REAL-shirt quest, so I wan't likely to give up on it!