Some guys in Lex land use throttle controllers since Lexus severely dampens the throttle response for smooth driving. In that case, the throttle controllers are good for increasing response. It's debated on actual long term effects since some people have had problems while others have not. It's on my list of mods for my GS either way!
In my opinion the Rav4 throttle is on the sensitive side (V6 at least), so the throttle controller could be good in the eco mode to soften things up and save some gas.
Another option to look into is Pedal Commander - more expensive but more features.