There are MANY MANY threads on tire reccomendations for the ES and other Lexuses, I'd do a search and see what information you can come up with. I had the same question in June and I know that thread was over 25 posts long.
I have the Toyo Proxes TPTs on my car and like them a lot, they are very smooth and quiet and supposedly have a 60k treadwear warranty although I've heard from others that they don't last that long (common). I would highly reccomend them to you as long as you never drive in the snow, mine are so poor in the snow as to make them dangerous. They really shouldn't be an all season tire.
I've never had Continentals but I did look at the Continental ContiExtremeContact and ContiPremierContact lines. I heard from some people that they ride hard so I stayed away from them. Typically the higher the treadwear rating the harder the rubber and the harder the ride.
Why only Michelin Toyo or Continental? Many other manufacturers make great tires. The Dunlop SP Sport 5000 is an excellent tire despite relatively short treadwear, but they're pretty cheap at $85 or so each, they come original equipment on several Lexus models. Yokohama also makes a good tire, the Yokohama AVS dB S2 is a very highly rated tire that is supposedly very quiet.
Michelin also just revamped its MXV4 line of tires with the MXV4 S8 that is supposed to be smoother, quieter, offer better handling and have better treadlife than the MXV4+ you have on your ES.
Lots of choices lol, I like my Toyos but I'll never buy another set because of the snow traction. We had an inch yesterday and I almost couldn't even get the car back up the driveway.