I don't have a favorite anymore since I discovered AG. I'm now experimenting with diff brands. For years, I used to use Eagle One, but only every 3 or 4 weeks, finding it a little too strong (the brown stuff literally drips away from both tires and wheels with each spray). In between Eagle One cleanings, I just used regular car wash soap. But now, I'm flipping between P21S, Optimum Power Clean (diluted) and ONR wash. I like these three so far.