Want to rent a car in Florence and return it to Milan 7 days later. What's good company?
Trenitalia or Italotreno.
What is your exact plan and itinerary?
Florence, Busca, Lake Como, Milsn
Not sure if you are referring to Busca in Piedmont, a very small town, or if you misspelled some other town, but if you are visiting a rural area then you should rent a car for that area. A car is not needed at all for Florence, Milan or Lake Como. A train is a much better choice for those locations given the traffic restrictions for non residents’ cars.
For renting cars in Italy I use AitoEurope, a very reputable consolidator. They have multiple websites, check all:
www.autoeurope.com
www.autoeurope.eu
www.kemwel.com