Range and cost is all it has. ROF is equal to worse, penetration is also worse considering its targets and the reduced damage is a huge issue since the unit needs at last 5 shots plus snare or 6 shots on its own to kill a medium tank. Considering also a slightly worse accuracy a Su76 will probably need about 7 shots or 33,1 secs to kill an OST P4.
Stug will likely need about 5 shots or 21,5 secs to kill a medium.
OK, i say'd it was on par in terms of price to performance with the stug. It costs less so it also performs less.
Like what more do you want form a 75f vehicle
60 max range(stug has 50)
170 max range pen(stug has 180)
3.875-4.375 s Reload(stug has 4.5-5.5 s reload)
fuel difference with mediums p4 45 and p4j 65 (stug has t34 0, sherman and cromwell 20)
fuel difference with special mediums Panther 110 (stug has t34/85 40, easy8 55, sherman-76 35, comet 95)
I don't know for me they look on par in terms of bang for buck.