The PWG/PWE gusts are derived by looking at the highest wind speeds in the lowest 3 layers in the model. The levels are 40m, 190m and 470m. In most cases, this is quite representative of the maximum expected gust. You will see on some days the gusts are more than 50%, but on other days the gusts will be lower. This is due to the stability of the atmosphere.
The GFS and ECMWF use a different method to calculate the gusts, using the instability of the atmosphere. Generally, the accuracy of the gusts in GFS/ECMWF is better.