LWB. Parts are harder to get, but there's less to go wrong. More unique, because fewer were imported. You can do a lot more and get away with it with a LWB (less electronics).
Again, the biggest downside is parts. Especially the interior. Most everything is either NLA or cost way too much.
So... I had a D2 and a LWB at the same time. I sold the D2.
Full disclosure: I tried selling the LWB so I could get SII. No takers, so I've kept it.
Good luck in whatever you buy. And, remember, no matter which you take, it's still a Land Rover. So be ready to suffer.