My Quiet One 3000 has a rattle to it: Even with a new impeller, shaft, and bushings.
I ran a Mag 5 for a few weeks: It had an annoying humm to it.
From all that I've read, Eheim is the way to go. But, they are bigger than most other pumps. I can't fit one in my sump's compartment, otherwise, that's what I'd try next.