Basically, that bit is like an advanced snaffle type. Due to the purchase and shank length, it still has a 1:1 pressure ratio, but because the reins are attached below the mouth and the headstall above, it functions slightly differently. Basically it will have a bit of gag action that a snaffle does not and it will have a bit of poll pressure that a snaffle does not. I am unsure whether or not you are supposed to use a curb bit with it, but if you do, it may have a slight curb action as well.
It doesn't look like a bad bit though I would have to actually handle and use one to give much more detail than basic mechanics.