In my shop I sell both, the 75th Hasbro has a beautiful paintjob, but the diameter is 24" an the shape is moch more on the comic style. On the other hand the King Arts has the correct shape and diameter, the correct shape for border and the correct bracket form factor, just a bit rough on their welding. The paint job is much different respect to the 75th (this one is more on the First avenger paint job similar to the Duplicolor's metalcast from Varor's thread for instance), the King arts should be a little more transparent to be accurate to the Winter Soldier paint job (resembles more the Age of Ultron than the Winter Soldier), but still a great piece!
Hope to have been helpful.
Regards,
Alberto