I've never used one like that, but I did use one years ago that put hard plastic blades in place of the string. The plastic was supposed to hinge if you hit anything with it, but eventually it snapped the flex shaft that connected the trimmer head to the engine. I'm not sure if it was the increased weight of the new trimmer head, or the repeated impacts it saw when the head hit stuff. I was able to replace just that broken piece, but I have only run string trimmer heads since then.
I'm sure if you had a heavier duty trimmer it may not be an issue. Mine was just a homeowner grade Homelite.