I'll be going MP All - simply because 30 years ago when I was sat at my Speccy watching a Python slip past me as I patiently waited to Torus Jump Drive the next step to the station I'd wondered about how cool it would be if that Python pilot were a human. I know I'm not gonna re-capture my youthful good looks any time soon, but I'm sure my imagination can still take me out to places today's technology - not to mention the laws of physics - can't.
Griefers don't worry me - you can get mugged if you're in the wrong place at the wrong time IRL. Likewise, richer people with shinier cars and friends that get those cars cheap for them don't worry me either - not much I can do about them.
I've played online multiplayer games for almost as long as they've been around, some are great, some awful. I don't really expect too much interaction with the rest of the online ED world , unless I seek it out or a game mechanic makes it imperative (although I'd rather hope not).
Exploits are my biggest concern. Someone mentioned somewhere the idea of hooking up with a buddy, selling your starting cargo, give you buddy the cash and deleting your commander - then start again and rinse and repeat until rich enough to jump straight into what you want - very probably affecting the evolving universe with the dozen or so portable stations you've decided to buy. I'm exaggerating for effect, of course, and I have no idea if this sort of thing is even possible but I do know this: if there's anything to be exploited, exploited it will be. I say exploits are my biggest concern but it's not a concern that gives me sleepless nights. I take heart in the belief that Frontier have an honest and genuine desire to deliver a game that's as rounded as possible. I have faith they're aware of most of the multi (and single, for that matter) player pitfalls and, given time away from fire-fighting alpha and beta bugs they'll do what they can to keep the playing field level.
TL;DR: MP All and looking forward to it, but not necessarily expecting to have to fight through the crowd to get the multiplayer barman's attention.