If you're looking for smooth ride, it's a no brainer, go with ES350. That's one of the reason I got mine. The ride is so smooth. Some of my friends are very impressed by how smooth the ride is, and one of them got a brand new BMW 5-series, which like the G, it's a SPORT sedan. They are great for fast cornering, but because of the stiffer suspensions, you'll feel every bump on the road.
Also, if you want realiability, stay away from Nissan/Infiniti. Their cars will be problematic much quicker than Toyota/Lexus.