Even I, a true Brit, can see why the Sten was not included in this list. As for the Owen, well the Aussies only ever built that weapon to take advantage of thier local metal pressing industries that were being unused.
The Sten has it's place in history, there can be no doubt about that ; if only for the fact that it could be mass produced by the hundreds of thousands so cheaply and easily, but it cannot compare from a qualitative point of view with either then Tommy or the MP40 both of which were engineered to a high standard that absorbed industrial production facilities to an unnecessarily high degree. Even the Americans were quick to recognise that when they introduced their little "grease gun" sub machine gun which was as "disposable" as the Sten. I can't comment on the Burp gun, but I strongly suspect that the Russians would have built this weapon just like they built their tanks - "Cheap and cheerful" - and none the worse for that. I have fired both all of the weapons mentioned here bar the Russian burp gun. The Owen made me feel like I'd be lucky to empty the magazine before the weapon fell to pieces. The Tommy was heavy and had a nasty recoil, not to mention a severe muzzle flash problem, but the MP40 was as sweet as a nut. It could be held on target reasonably easily and was comparitively quiet- all one had to do was to keep one's left thumb well away from that bloody bolt or else you'd soon be crawling around on the deck looking for the top half of your thumb !