i've never heard the kenwoods, so no comment.
the jl's dont sound all that great to me, i've heard them in a few setups and in two sound boards, all sounded muffled, just not that great.
the infinity's i dont like either, they have a harsh tweeter and no midbass, not my kind of setup, i heard these in a car, and in a sound board, they sounded worse in the car, so it could have been the setup.
so i guess its the alpines, they sounded best from the bunch, good midbass, smooth sounding highs, i liked them, surprisingly, since i dont like the other speakers they make.