Peter Berkowitz reports on the only substantive difference between the parties:
It concerns the future of Israeli settlements, the towns and cities built and populated by Israel in the territories it gained control over in 1967 in the Six Day War. While he almost certainly would not build new settlements, Netanyahu remains unlikely, without pressure from the United States, to freeze the natural growth of existing settlements. In contrast, both Livni and Barak would probably impose a freeze on all new building beyond the Green Line. Livni and Barak recognize, however, along with Netanyahu, that the settlements are far from the fundamental obstacle to peace with the Palestinians.
In this last sentence, Peter presumably means they are not the fundamental obstacle to peace for Israelis. That's obviously not how a lot of Palestinians feel. And the notion that Israel might force the removal of the settlements - a precondition for any two-state solution - is looking more and more surreal. The piece helps explain, however, how Iran remains the central interlocking piece for any attempt to move past deadlock. Since no Israeli will accept any actual rapprochement with Iran that leaves the Tehran regime in place, and since Avigdor Lieberman looks likely, in Berkowitz's view, to gain a staggering 17 - 19 seats, the future looks grim for any serious deal-making.