I use it without any problem. I iron it on in strips about 24" long so that I can keep it straight while I put it on. Just remember that poly batting is a no-no with the iron. I've used it without problems on Hobb 80/20, Pellon Legacy and Hobbs Washable wool bat . also, you can cut "French Fusible" (the stuff that looks like a lightweight Knit with fusible on it ) into strips to use--but the tape is about the same price and less hassle.
When I sometime sew bat pieces together it seems like I end up with them being "bunchy".