I like the Rainmaker, sold by Michael Olajide Jr. It does hurt when it hits you though.
Any of the light weight ones or fabric seem to tangle when I use them, which is very annoying but they don't hurt when they hit me!
ETA: I do have an airope, which is similar to what pcdoctor01 posted. I do get a good workout with it but I definitely don't engage as many muscles when I use it. (Especially in my core area)