I had a Black Lion Audio PG-1 for a while. It was a rocket ship of a power conditioner after using cheaper Furmans for years. Gives you a good display up front for wiring faults, abnormal voltage, if your ground is OK, etc..
For a little more the Furman M-8X Voltage Regulator is worth a look. I have a few older Furman power conditioners - including one formerly owned by Brad King, I'd get the M-8X, or similar, if I was looking for one today.