Just got my IS300 watch today from my local Lexus dealer. The watch came in two size. A small (female) size and large (men) dial size.
If you are ordering the watch from a online retailer make sure you know the size of the watch that you want. (picture is hard to tell, the actual size between the small and large dial) You should know that the female size (small dial) is already in a good size similar to other Mens watch.
The small dial measure around 1.25 inch / 34cm in diameter. (edge to edge) I did not get a chance to measure the large dial. Maybe someone here has all the exact measurement. But it was big.
In my personal opinion, unless you have a large wrist, I think the small dial will fit best for most people.
I paid $230 CDN with Tax it came to 264.50 Cdn. I think is cheaper than the US site.
Converting that to US is only around $170.00