Front-firing or down-firing, which is better on concrete?

[Zman2k2]

So I'm going to be in the market for a sub upgrade soon, and I'm also working on a theater room in the basement. In the dedicated room, I'm going to have laminate flooring, pretty much right on top of the concrete. While reading this thread something came up that I've never considered before. Does the type of floor effect output? Would I get better LFE output from a front-firing sub on a concrete floor than a down-firing sub on the same floor?