It's an interesting place - some old exhibits that are very interesting, some old exhibits that are just a bit rubbish, some newer exhibits that are superb.
Some interesting animals too - loads of Nile Lechwe and Japanese Macaques, Lappet-faced Vulture, Schneider's Dwarf Caiman and Cape Cobra. Also keep an eye out for my 'mystery' macaques (http://www.zoochat.com/701/macaques-bioparco-rome-15-10-09-a-111871/); would be interested in a second opinion!
A word of warning though - keep an eye on closing time - we nearly got locked in as the only exit seems to be through the shop and the door out of the zoo into the shop cannot be seen from the tills, so you need to make noise if you get stuck in! That'll teach us to try and do other sightseeing on the way to the zoo so we 're not at the zoo 'til lunchtime...
And enjoy the city, as well, of course - one of the greatest cities I've visited.