Buongiorno,
I have not used the tour that you have referenced however, I can say (unless you have trouble walking around ) Florence is also very walk-able and pleasant by foot. So if you are thinking that you need to use a bus tour because everything is spread out...well that isn't true. And you can use a local city bus to get up to and down from Piazzale Micheangelo with no problems (ATAF bus number 13 or 12).
I have used this type of tour for other cities - and if you are on the last leg of your journey and just want to have a fun ride about - then yes this type of tour can be great.
Buon Viaggio,
Donna Denise