blacksc400

iTrader: (4)

Had 2 IS300 both manual and auto, also had 1 Es300 and 1 Es330.

The ES300 is more reliable, except you need to change oil every 3000 miles.

IS300 had couple thing went wrong, but all easy repairs.

I would go for the IS300, even it's smaller inside, but it's wayyyy more fun and more modern.

OceanView

I've only owned an ES but mine has been pretty reliable.
Just routine maintenance and a few things here and there.
Still on original engine and transmission with 333K miles.

Hoovey689

iTrader: (16)

Overall the ES should be more reliable, but IS wouldn't be a bad choice either. Honestly just get whichever you prefer. Make sure to test drive both though if you haven't already.

Fizzboy7

Both are well built and both get high marks for longterm reliability. I'd do the ES, simply because the IS was likely driven harder. ES should get a bit better mileage too.

Aron9000

If its a taxi/livery service type of deal, ES300 all the way. More rear seat room, cushier ride, and most importantly better MPG. I have an SC300(I know not an IS300), same 2JZ/5 speed combo, that thing drinks premium fuel worse than the LS1 V8 Camaro I had. I'm talking 16-18mpg in town, 21-24mpg highway, using premium fuel.

Big thing with the ES300(or any Toyota with a V6) is to make sure the oil was changed every 5k miles, if not sooner. Short trips where the engine doesn't warm up is murder on the oil in these engines.