No question you should get the split. Wrath your recommendation is probably good, but I think Jones are the boards being offered to the OP. Get the Solution, it's the same as the Flagship. So you'll know how it rides. Try to rent split bindings too. Spark or Karakorum set up is preferred. Also make sure you have collapsible 3 section poles with some sort of flick lock system. Twist locks suck and they jam frequently. You don't need to be dealing with that.
As far as the ride goes. I don't really notice a difference at all torsional wise. Mostly because you are putting a huge metal plate across the board negating a lot of that flex because of the split. The biggest difference is weight. The split will weight a couple of pounds more than your Flagship.
In terms of effort put out, you are going to put a ton out. You'll have to use a lot less with a split than carrying a board on your back and snowshoes. Not to mention if it's windy a board on your back is like a giant sail. No fun at all unless you are out sailing....