Not just showing off, as the Sten could be fired and reloaded prone much more comfortably than an MP40 due to its magazine design.

Magazine capacity of MP40 = 32 rounds

Magazine capacity of PPSH with drum mag = 71 rounds

I'd be tempted by the additional firepower if my life depended on it.

Regards,
Andrew

Yes, I think I would too!

The 'extra firepower' aspect was very much felt by the British and Commonwealth forces in the early years of WW2, until such time as sufficient Brens, Thompsons and Stens arrived with front line units. I have a set of books published during WW2 in Britain, with the 1940-41 volume having a number of shots of (fairly ragged) Western Desert force/7th Armoured personnel proudly brandishing an MP40...perhaps one of the few that they managed to actually capture, but in the absence of any other light automatic weapon, then good enough for the camera/propaganda shot. The caption is, inevitably, something like 'Our men in the desert are equipped with the latest automatic weapons'.....ho hum!!

Graham,
sticking to the actual subject, it seems obvious that the often-documented use of captured soviet SMGs is simply related to the sheer scale of warfare on the Eastern Front and the correspondingly large troop masses.
In addition to the numerical scale, the Red Army was comparatively well equipped with submachine guns.
After the effective demonstration of the potential of SMG armed troops during 1940 Winter War, the Soviet military rushed the production of large quantities of its own models.
With production figures of well over 8 million PPSh-41s, PPS-43s and PPDs in total, Axis troops were able to capture large numbers, especially during the offensive campaigns 1941-43.
The bigger (but not always reliable) drum magazines aside, soviet weapons basically offered a certain robustness, easy handling and satisfactory firing performance & effect.

Apart from the ubiquitous MP38/MP40 and other domestically-built models (MP18/28/34/35 and Erma EMP), foreign submachine guns used by German troops worth mentioning were:
italian Beretta MAB 38
czechoslovakian ZK 383
french MAS 38
finnish Suomi KP/-31

They also made extensive use of czechoslovakian light machine guns ZB vz. 26 and ZB vz. 30, renamed MG 26(t) and MG 30(t).
These can easily be confused with Bren Guns, as it was a replica of the excellent czech weapons.

By the way, Caesar offers a nice 1/72 set of early WWII German infantry with 2 mentioned & less known weapons (early german MP & Czech light MG).

http://www.plasticsoldierreview.com/Review.aspx?id=1377

Hello,

I would like to comment on this matter that many German soldiers reported after the war that the advantage of Russian submachine guns was, that they were specially designed for the conditions of war under "Russian circumstances" (extreme cold, snow and mud in the weapon mechanics). So they still worked at -20 degrees and with a lot of pollution. Under these conditions, the German MP 38/40 showed permanent malfunctions.

In addition, the German side often had problems with the ammunition supply. Russian ammunition, on the other hand, could be easily found in the bags of every Russian prisoner or fallen soldier.

I have a book here, written by an old german veteran...he wrote: "In spring 1944 we often organized counter-attacks against russian positions, just to conquer ammunition and food from the russians."

Many "foreign weapons" were also regularly issued to the Wehrmacht divisions in 1940, which were then build up (so-called 3rd wave). There was simply not enough equipment available to equip these new divisions, so Austrian, Czech and British weapons (captured in Poland) were given to these units. Since there were only limited stocks of ammunition for this weapons, they were mostly replaced by German weapons until autumn of 1941.

Just to tack onto what others have said, you are right to have the suspicion that the NSDAP supporters (as we officially call the WWII "Germans" here in Berlin) well known notions of cultural superiority carried over to the belief in their equipment types compared to what they perceived as their historical "Slavic" enemies prior to the invasion. However on the Eastern Front this only lasted until the Autumn of 1941, when designs such as the T-34, KV-1, and other such sophisticated inventions made it abundantly clear that Soviet equipment could be useful when needed.