No, there won't be, unless they are fucked up or it's time to do some maintenance.
What science says is that only PRO's can really benefit of getting some much much more expensive. Apparently aero wheels "kick in" at 40 kmh or so, and honestly, I don't think you will feel much difference. What you will feel is the effect of wind!
I'm not sure if @ranlee really meant it, but he said that the deeper the section the lighter. That's not true. While may be for structural reasons you can may be make the walls lighter if they're deeper, the more material (the deeper) the heavier. Aero rims are not famous for being light, although of course the most expensive ones are pretty light.
There's a whole debate going on about this, really. A guy who smashed dunno what climb's previous time on heavy rims (aero VS "climbing"?) argued that they have more inertia, so once moving they keep moving better.
Again, if you do flats, if you are not a pro... buy them only if you want a different looking. Or at least be warned that you won't have better performance, even if the money makes you believe it