I've got several styles of the "springs" that fit over the needles to use for darning. The problem I see with them, is that they don't' touch the fabric until after the needle has penetrated. This is where I've had problems, as if you are not going slow and paying attention - you can be moving the fabric while the needle is in it - and that can cause all sorts of problems. With a hopping foot - it presses down on the fabric right before the needle penetrates, and stays down to hold the fabric from moving until the needle exits.
I dont' really know if this would be a big problem - but we've also had discussions about length of needle and problems that can arise if the fabric is moving while the needle is still in it. And that is also the number one reason my main machine has a chewed up needle plate.
I have FMQ on my main machine with the foot pressure set to near 0 - which pretty much allows no pressure down with the foot. I had to go quite slow or I'd miss stitches - and if I missed three in a row, I'd usually end up with the thread breaking as there would be too much loose thread below the tensioner at that point. I've not found a hopping foot that will fit on that machine so I can't see if that would be better. However I've used a hopping foot on several different Singers and also on my Bailey with no trouble.