It's a shame you didn't shoot the Sterling. The mags are a LOT easier to load (no tool required), and you can literally shoot it with one hand since the pistol grip is at the center point of balance. I love mine!
The very first Sterlings were issued right at the end of WWII but were known at the time as "Patchetts." They originally used Sten mags, which were superseded by the curved 34 round mag with the roller followers developed for the Sterling in the 50s. It is probably the pinnacle of development for old school subguns.