Overall I found the public transport system in Rome was extremely good.
Our accommodation was just outside of the city centre, so it was necessary to get a bus and then the metro into the centre.
The buses ran reasonably regularly, approximately one every 20 minutes (as there were two routes we could choose from), and the bus stopped at the metro station. Again the metro was a regular service, approximately every 5 minutes.
Paying for the bus was somewhat different to England. Here we buy a ticket from the driver as we get on, and I was expecting something similar. However, when the first bus we used arrived, everyone crowded on, and there was no way to get to the driver. I did panic somewhat that we would find ourselves fined at the other end for travelling without a ticket, but when I finally spoke to the driver he was unconcerned, and just pointed to the metro and said to buy a ticket there. Tickets were either by the hour, daily, 3 daily or weekly.
As the holiday wore on I noticed that only rarely did people put their tickets in the validation machine on the buses, and most people just jumped on and off without even getting tickets out of their wallets.
The metro was slightly more payment conscious, there were turnstiles at every station. Although I did see a few people jumping the stiles. There were two types of metro trains, some clearly old trains which were covered in graffiti and had no air conditioning, just opening windows. And new trains which were clean and air conditioned. Begging was rife on the metro, either by pregnant women or children playing accordions. However, they weren't persistent beggars, they put their hand out and walked on at the shake of a head.
WORD OF WARNING: I was almost pick pocketed at one of the stations, a boy of around 12/13 kept getting in my way as we were trying to board the train, I thought at first he was trying to get back to his parents as it was busy and people were pushing everywhere. However, as I looked downward he snatched his hand away, and I noticed my bag had been unzipped. Luckily my purse was still there, a few seconds later and it would have been gone. The boy jumped off the train just as the doors closed, and I saw him meeting up with a group of other boys his age.
At the moment, part of the metro A line is under refurbishment, so when we went on our trip to the Vatican we had to leave the metro and use the buses which had been put on. This wasn't as easy as it sounds as only one bus was being used at any given time, so the queue was huge and as soon as the bus doors opened the world and his wife charged to get on. This meant we were packed like sardines for the first part of the journey, eventually as people got off it was possible to breathe again. The second problem was deciding where to get off, on the metro it was clear which station we needed to get off at, but I had no idea which bus stop to use. Eventually I decided that a lot of people would be visiting the Vatican, so decided to alight when the most people got off. Luckily that worked.