The experience of a place like this is always going to be a bit pot luck, depending on the particular exhibitions. We were fortunate - lots of hits as well as some misses. The building is quite impressive but could actually be plonked in any city suburb - it didn't resonate as Roman or Italian to me. The buffet lunch was quite good - quite a lot of choice, even for vegetarians. A bit pricey - probably similar to what we'd pay in a restaurant for lunch, but good choices.
Important point - our guidebook (new!) and some websites say that they have a Nintendo based treasure hunt for children based on the current exhibitions at any time. They don't any more. One highly disappointed member of the family. And his Dad.