Had my '08 ES 350 almost 5 months now. Ultra Premium with Nav. (Canadian combination). My previous car was a well equipped Accord.
No car is perfect, but you can look forward to a nice quiet and comfortable ride with the ES 350. I especially enjoy the highway ride. I drive about 45,000 kilometers a year so this was important.
A couple of weeks after ordering the car, I received a call to say that Lexus Canada was including regular maintenance for the first 80,00 KMs. This, because of the difference in US / Canadian dollar and sticker price.
Heavy rubber winter floor mats were included with the purchase. I think that this is standard.
As expected, the stock all season tires were not good in snow, but I didn't expect winter tires to be so expensive. I suggest you price this out in advance. Even if you only change the rubber, it is fairly expensive due to the tire pressure monitor and the need to recalibrate with every tire change. If you buy winter tires and rims from Lexus, expect to pay $2500 plus tax.
I have experienced a rust perforation issue on the rear exterior of the trunk lid. Appeared as a pin hole sized spot that was clearly through to metal. Not caused by any sort of impact, but rather was a paint flaw. Haven't seen any other posts about rust so I assume it is a rare situation and it really shouldn't influence your decision. My dealer is working on the car now (under warranty).
In the end I suppose choosing a car you will really like is a personal thing. Good luck with your Lexus.