I knew a gentleman, now alas gone, who fought in the Polish underground in WWII. The Russians supplied them with those "Pa Pa Shaw" subguns and he considered them the best of the WWII guns. He had used the MP.38 and MP.40 ("borrowed" from Germans who didn't need them any more); STEN's, provided by the British; PPS's, also from the USSR; and one Thompson. He considered the PPSh the best of the lot.
He admitted not having fired the Thompson much (he later fired mine quite a bit). It was taken from a German motorcycle messenger who was carrying it in a scabbard attached to the bike. One night, the German managed to encounter piano wire that had somehow gotten stretched across a road, and his head went one way, the bike the other, and the Poles got the Thompson. The German had only two magazines (40 rounds) of ammo; the Poles fired that up just to see how the gun felt (they had seen all the gangster movies, too), and then threw the Tommy gun in a lake.