Added after this initial pistol but after reading. Great article, kits of background and information. They made the comparison more interesting and logical than I initially thought it would be. 
Without reading it, I will it sounds interesting, my first initial thoughts are. Its hard to compare the two as they were intended, to my knowledge, for differing roles. The M1 carbine was designed to basically  increase the fire power of support troops over the pistol. Obviously it's role ended up way beyond this, but those were the parameters it was designed for. 
The STG44 was designed as a intermediate caliber main battle weapon, not to be be confused with the full power battle rife, but to replace it in many applications, but it was bever issued in large enough numbers to make a huge impact. 
This is what I was taught about them both. Will be interesting to read a comparison.