I have used Rough Guides for many years because I have always found them very useful. Good tips, good background information, comprehensive, good maps. The Italy guide is not bad, but personally I doubt whther it makes sense to make travel guide that covers the whole of Italy. There is just too much to see and do in this big country where history began to leave traces already such a long time ago. Wherever you go, you are bound to need additional documentation on the area where you are. The guide covers a bit of everything making it ideal for instance for someone who makes a round trip of one month, covers the whole country and only wants to see the main sights. But who does that? I will give an example of my 2 trips to Italy this year. First I went to a small village in Liguria. We rented a small house there, so were fixed to one location for a week. That means you want to see things in the neighbourhood. On half an hour drive there was the village of Dolceacqua. It has a huge history, a castle, a historic centre and a spectacular old bridge that was even painted by Monet. Yet the guide makes no mention of it. Without other sources we would not have heard of it. A second trip was to the neighbourhood of Rimini. We were in the Valmarecchia which has so many nice old villages. San Leo was mentioned but for instance Sant'Agata in Feltria with a 17th century wooden theatre and a 15th century castle (amongst other things) and Pennabilli not. So here again we needed additional information.
If you go to places that are extensively covered like Florence and Rome, the guide will probably be worthwhile. If you want to explore a particular region, this guide will not be of much help.