If you want the peace of mind that surge protection brings and/or cannot install dedicated lines, then you could do a lot worse than a Duet.
In my situation moving one of the outlets closer to the system is not an option, so some kind of "extension cord" is required. I've tried a few alternatives and several years ago bought a VansEvers Clean Line (VECL) that has been in service since.
Recent system improvements brought to the forefront a previously subdued sharpness to "S" sounds on vocals. The character of this sibilance varied with each duplex of the VECL, but it was always there. Replacing the VECL with a Duet removed the sibilance with no loss of detail. If anything the Duet has added nuances of clarity and certainly hasn't subtracted anything.
BTW, my Duet only has a CD Player and tuner plugged into it. The amp is plugged into the wall. I do not know firsthand how it works with higher voltage equipment.