Go with the machinegun if your indecisive with permanent upgrades. basically choosing balance between the four stats, with fire rate being its root stat.
would be a good game if i hadn't bought the M24 only to discover it doesn't work in areas...and i didnt look at the comments til a used up all my money and ammo trying to break the damn satellite
Money maxes at 99999 :( Great game though. 4.8/5. I am also wondering if critical improves dmg when rate is maxed. Guess I'll have to play around with it and pay attention some more.