Railgun, I choose Rapid Fire because of followup shots. In my experience I am rarely caught reloading as opposed to having enough bullets, with the ARs anyway. The lack of speedy followup shots means that even loaded there are some extensions you cannot get in time, whereas with Rapid Fire you can guarantee another notch on the rifle as the odds of being caught short are low with Large Mags and Tactical Reload (makes me reload more often, usually full gun the moment I can breathe).
2 other reasons though: Firstly I am completely indifferent to all Zed Time skills, usually I see what they do at 25 and just pick whatever (only one I have a preference for is Zerk's Spartan as you can feel like a ninja or something). Second reason is yes, more ammo makes me enjoy blasting stuff slightly more indiscriminately (in my eyes it is more fun than total minimum-resources precision/pragmatism, which is always an option but just not the one for me).
2 other reasons though: Firstly I am completely indifferent to all Zed Time skills, usually I see what they do at 25 and just pick whatever (only one I have a preference for is Zerk's Spartan as you can feel like a ninja or something). Second reason is yes, more ammo makes me enjoy blasting stuff slightly more indiscriminately (in my eyes it is more fun than total minimum-resources precision/pragmatism, which is always an option but just not the one for me).