The thing holding ronda's auto price high right now is scarcity. She was only in 2 series of topps so far..and in the last one(bloodlines) she had a grand total of 191 autos..total. in finest, her base was a short print and she had 38 total numbered autos. In mma cards, that is nothing..
topps can choose to be smart and continue to short print her autos, keeping demand higher than supply..or they can flood the market with newer ronda autos, which will serve to lower the prices on all of her cards. TUF will have less impact on her prices than what topps does in the upcoming KO release...
Twoten knows his stuff and if you are really looking to invest in mma cards, the ones he listed are the grails of the hobby.. you can always diversify with a ronda auto as well.