After reading what was posted here and inspecting several RAV4s with the factory bumpers and various aftermarket hitches. I ended up deciding to go with a Hidden Hitch instead.
BTW the factory bumper does have loops for hooking chains but the are hidden on the inside where it lookes like they would bend the lower aluminum on the bumper if the safety chains actually came into play.
My additional reasons against the factory bumper/hitch:
1)the bumper appears to be nearly nonfunctional as a step
2)it doesnt appear to be sturdy enough to significantly aid in a crash while at the same time just tacks something down low making it easier to snag something on while backing or in marginal clearance situations
3)the aluminum of the rear bumper really doesnt match up with the rest of the vehickle and appeared to be just a tacked on afterthought. This effect is lessened on the RAV4s with the aluminum side step rails (which also are next to useless also)
The reasons why I went with a Hidden Hitch are:
1)price: $109 including a draw bar, hitch pin and receiver cover and free shipping from JCWhitney.com. (The snap-in wiring harness added $32 extra to my total).
2)tow capacity just a bit stronger than the factory bumper hitch (2000lbs versus 1500lbs). The vehicle still limits you 1500lbs according to the factory manual but I like to know that my hitch isn't the weak link.
3)It sits a bit higher/more recessed and appears less obtrusive than similarly rated Reese or Draw-tite brand hitches.