The reviews are a little over the top, for sure...but the effect of changing out the contractor grade outlet to a $10 IG-8300 one at Lowes is a surprisingly beneficial swap

The difference has been repeated in 3 houses now.
The jump to the next step (a $49 PS Audio outlet or $36 Porter Port) was murkier in benefit. As I got not much further in benefit, I won't be trying any $147 one.
But, the step from $0.49 contractor special to $10.00 hospital grade is an
essential part of my system now. The system loses a little stridency when you toss the contractor grade ones that your house came with.
Of course if you have some MOV's, most active power filtration or even Brickwall-type power filter (all tried here), you may never hear the benefits of a simple outlet swap to the Lowes $10.00 IG-8300 as your system is plagued with ugly sound downstream from the above.
For audiophools, it's MOV's, most or all active power filtration and Brickwall-type power filters that should be avoided at ALL costs
John