I would say the 300h will be the best for you from what you have said - and comparatively easier to find.
I have yet to find a human being hate on the IS300h CVT after driving it - of course, motoring journalists don't come under "human being" as they are some sort of super human racing drivers
The IS300h BHP figure is 220hp combined. If they are quoting 178hp, they are stating just the engine HP and not the combined HP.