I have a 3rd gen Acura TL and have no complaints. The nav and voice control etc are superb and I haven't had any problems in 4 years. I am trading up to a gs460 as I want rear wheel drive, a v8 with over 350 hp, radar crash avoidance etc. I looked at an RL but it just doesn't have enough hp. I've never owned a Lexus nor an Infiniti but I think it boils down to what options you want and what you want to pay. I don't think you will go wrong with any of them.