I have Lasalle and have read them but haven’t played them. I have Black Powder and have read and played them. They seem to be different games and I’m of the mind that they will both satisfy different requirements on gaming. BP a more generic quicker playing game and Lasalle a little closer feel for the period with a bit more detail. I don’t think you go wrong with either system. Agree with Not Connard; I have Napoleon and couldn’t finish reading them.
Chickens got livers? I'm gettin' some!