I'm a reporter, and I don't quote the ums or uhs. Very rarely, I'll use ellipses or brackets to clean up quotes, but I try to avoid it. Of course, and this goes without saying, actually changing what someone said to make it sound better is unethical. If they didn't say anything directly quotable, you can fall back on the "she said that ... " construct.
My rule of thumb for quotes is that I only use them to express things that I can't state as fact. It drives me crazy when reporters use quotes like, "The meeting starts at 9 p.m.," Smith said.