I stayed at the Cavalieri on a work conference earlier in the year. It is dated (hard to put my finger on how but I would say it has a 60s kitsch vibe to it). The pool area is nice as is the rooftop view. Along with my room being massive (not sure of the category, that is about it in terms of positives.
What I found surprising was that for a hotel which has a 3 star restaurant, the rest of the dining in it was garbage (i.e. by far the worse food I've had in Rome - including tourist-y pizza places).