The year is 2000-2003 what are some of the disadvantages of both? And the Pros?

Screw the 300. The real quality is with the 350. But ES is the way to go, with smoother handling, mileage aint to shabby, a sleeker look, and a little less noise in the acceleration (this applies to speeds over 50 mph). This site does a good comparison for you http://forbesautos.com/gallery/2008/lexus/es_350/?partner=a

They are completely different. The IS is a rear wheel drive platform while the ES is a front driver. Personally l prefer the IS models. The ES is basically a fancy Toyota Camry.

Lexus IS300 depends on less luxury but more performance, mostly like a sports car.

Lexus ES300 depends on more luxury but less on performance, its like a Toyota Camry but more luxurious.

l like the IS better. It is sportier and it looks better. The ES is an old person is car. It is the most boring Lexus and they do not look very good. They basically have the same features as an IS, but with the IS, you get some excitement. l do like the 2007 and 2008 ES, though, but the ones made before then are not so great.