Another vote for open. The pros far outweigh the cons, and makes ED much, much more alive and fun.

First, right up front, you're gonna get killed and it might not be fair. It's gonna happen, so just make sure you fly with insurance to keep from getting wiped out.

As has been said, there be player pirates out there. The majority of which, in my encounters, are RP'ing pirates and they make the game universe better. If you're in a pirate infested system (rare routes for example) you can't just set 0.07 on the clock and cruise in. You have to plot an evasive course and watch your six. And if they catch you, you have a choice: dump cargo, try to make a run for it, or fight your way out. The first time it happens you'll probably fight it out and if you're outclassed, die. Then be pissed. Take a deep breath and think about how little it would have cost to drop a few tons of cargo vs a ship rebuy. Then, after that, start noticing how much more interesting Supercruise gets when you actually have to pay attention. It's a whole new ballgame.

Then there's the social aspect. Hop on the local channels and say hello to your fellow commanders. Find out what's happening in the local system, who's fighting who. Wing up with some people to go bounty hunting, or if you're wanting to pirate, someone who will slap the parrot on his shoulder and go aarrrrr with you. It's definitely more fun with friends.

Then there's the "there's life out there" aspect. Seeing 20 pads lit up in a station with ships coming and going is pretty cool, as is trying to navigate past them in the slot. The other day I landed at one of the CG points and switched to the debug camera just to watch ships take off and land. Almost makes you feel like a spacer.

Open's the way to play. Just remember to make your insurance payments and not to take anything personally.