We took a ship's tour to Florence and the giuide was good, but had a speaker system which was crackly and inadequate, especially with so many other tourists and tour groups around us. We did see teh essentials and had time to wander on our own
To arranged a priovate tour with RomeCabs and this worked out well. We had two vans and they stuck together all day, despite heavy traffic and limited parking. We saw a good piece of Rome. Pirymid, Colosseum, Forum, Trevi Fountain, Spanish steps, Vatican. The latter we had a guide arranged by RomeCabs who was great - she had a transmitter with individual headsets which worked well. The only disappointment was not stopping at the Emannuel monument - we saw it, but only from the vehicles.
Took the Hop on Hop off bus and then walked round the town. We were coming back to spend a few days there, so we checked out our hotel on Rossio Square. Our son and d-i-l took a Segway tour and felt it was worthwhile.