Every company has their own rating scale. They're not interchangeable. As long as there isn't a huge discrepancy between the flex of your board and bindings, you'll be just fine.
For starting out, I think softer is better in general. It's just more forgiving.
"People say that marijuana smoking is going to get in the way of my career. I say to them that on the contrary, my fighting career is getting in the way of my marijuana smoking." -Nick Diaz