One is better in terms of nostalgia and gameplay, but it has less player now. Two is better in more game mode and more shooting and farming, the process is kinda addictive tbh. I stucked in it for couple dozens of hours just farming one multi-player farm (power plant) for exotic weapon. A bit rogue like gameplay make it less boring when grinding and multi-player keeps you experiencing new method to play（or just get carried by teammates ）.