I prefer the two that meet in the middle; seems easier to me to setup and take down; more control over the part of my tarp that's still wrapped up. I don't suppose it makes a real big difference though. I find that mest are lighter weight than the silnylon ones I started with. Another very minor considerations is haveing one big ball of snake skin on our ridgeline on only one side versus two smaller bundles, one on each side. I think it looks better, more balanced with the two.
The material is a bigger consideration in my opinion, I like it to be light weight and breathable.