Anyone used a AR Extendariser Picatinny Rail Clamp-on Mount 20 MOA?

I have not used that particular one from EGW, but generally speaking, most AR risers, including those with some forward cant, will be somewhere around 3/8" to 1/2" in height.

I will tell you that the $125 pricetag of the EGW is enough to turn me off of it when the WOA riser is ~$88, the Badger Ord (depending on how much forward real estate you need) is ~$90, and the PRI is only ~$80 and all of them offer between 20MOA and 22MOA cant.
 
EGW 20 moa riser product description from Brownell's:

SPECS: 6061 T6 aluminum, hardcoat anodized, matte black. 8.875” (22.5cm) long, 1.125” (2.9cm) wide at base. Adds .600” (1.5cm) to height of flattop at rear, .570” (1.4cm) at front. 7.7 oz. (219g) weight.
 
I have the WOA rail on my AR. I use it to get the scope further forward, the 20 moa is just a bonus. It lifts the back of the scope up about 1/2 an inch. I use a magpul prs stock to get a good cheek weld. The prs stock had plenty of adjustment to get a good cheek weld with the riser and low rings.