I don't know which one of the clamp-on ones feels better, but I can tell you which one is less ugly... the metal one looks cooler lol.
I am actually planning on sending one off to get threaded once I decide whether or not I'm going to change the receiver over to a SRP cartridge next and get the bolt-face bushed at the same time... though, if I wasn't getting anything more done besides threading for a knob I probably wouldn't bother because I'm sure one of the clamp-on ones is fine.
FWIW I had a Howa 1500 with the factory threaded knob they offer randomly, and IMHO that knob was a little ridiculous (giant) for me, it was much better with Area419's Rem700 knob, but that sucker is long and hangs out there, and IMO actually made it harder to run the bolt smooth (much bigger "bridge" to make with my thumb and I have larger hands too).
I vastly prefer the feel/size of the "normal" 1500 knob, a slightly larger one would be cool though.