FWIW, I too have both rifles and have fired both.
The charges levelled against almost everyone by Johnson supporters were absurd and probably caused Johnson more trouble than anything else. There was a lot of politics involved, with the anti-Roosevelt faction condemning the Army and backing Johnson. In addition, Johnson was a Marine reserve officer, and many Marines just automatically took the side of a Marine, regardless of the quality of the rifle. It was even claimed that Johnson "knew what he was doing" because he had served in combat in WWI, something that was plainly not true (Johnson never made any such claim).
The usual pro-Johnson line was that the Army hated Johnson and his rifle because it was not developed by the Army ("not invented here") and that the generals backed the inferior Garand because it was a Springfield Armory development. (Garand was slammed as something close to an incompetent crook, even a "foreign" traitor.)
In what seem to have been reasonable and fair tests, the Johnson came in second best. Johnson claimed that the army should have "two arrows in its bow", in other words, two good rifles, one of which, of course, would be his. Had the Johnson been adopted, there would have been FIVE rifles in U.S. service in WWII - the others being the M1 Rifle, the M1903, the M1917 and the M1/M2 Carbine.
The Johnson did have some advantages, already mentioned, and would have been easier to clean after firing corrosive ammo. But I have always considered it as not being fully developed. Further, it is an awkward rifle. The light bayonet mentioned above was necessary because the rifle was short recoil operated and the conventional M1905 bayonet was heavy enough to interfere with the rifle's operation.
(If you want a modern comparison, look at the health care bill; almost none of the rhetoric on either side actually involves the content of the bill, only the lies told about it, for and against.)
Jim
