i've no intention of trying to dissuade the OP from staying in Florence at Christmas - in fact I think that would be far preferable to a whole 5 days at the resort they have booked, for which I would suggest 3 day max.

macanimals - I think the difference is you stayed in towns that had things to do and choices of restaurants at night, not somewhere remote.

I also understand the blog promoting winter in Tuscany since it's by a B&B owner. I'm sure they don't have much business that time of year.

I love Florence in winter. it is the only time in recent experience that it wasn't packed to the gills.
Although we DO like countryside, I think cities make much more sense in winter. The resort experience will be a resort experience. I think it would be very very boring after a couple of days.
Days are short in winter, so driving easily is limited.
Again, I concentrate on Florence.

I spent last winter in Rome, including Christmas, and it was wonderful. Christmas afternoon with the Pope in Piazza San Pietro, regardless of religious beliefs, was a special experience. The city was beautiful and lots of people all around. The only inconvenience was that the buses weren't running on Christmas evening so I needed to walk instead. I would highly recommend Rome for Christmas!