Should we stay in Siena or Montepulciano ?

The cities are apples and oranges. The diversity and the opportunities are far greater in Siena. I think Montepulciano is a good day trip location.

Q.1: Do you plan to have a car?
If the answer is no, then stay in a city like Siena, which is the transport hub for the province of Siena, in which Montepulciano is located.
If the answer is yes, then the choice is entirely yours, because with a car you have freedom of movement and full flexibility. Siena is a quaint medieval city, not a small town.
If you prefer to walk around a larger urban environment in the evenings, after your day trips, then Siena is for you.
If you prefer a smaller quieter village/small town setting, then Montepulciano or Pienza or other places in the area, are for you.
There is also an even quieter setting, which is a Villa hotel or countryside resort in the middle of the countryside. Some people prefer that.
The choice is yours. In terms of hotels, you are more likely to find large upscale hotels in a city like Siena rather than in a small town. Although there are some fancy resorts in the open countryside of that area.

In Montepulciano a more upscale resort might be the Etruria Resort and Spa.
Nearby in Bagno Vignoni, there is also the Adler Hotel, another resort and spa.
If you like golfing, then La Bagnaia Resort might be for you, closer to Siena.
In Siena itself, the Hotel Garden offers a Villa hotel environment within the city.

We’ve stayed in both, love Montepulciano, don’t care for Siena. And I’m a city girl. That said, we’ve stayed at a wonderful property on the edge of Siena, twice just to stay there we like it that much. It’s called Borgo Grondaie. A series of little houses/townhouses, beautiful lawns/gardens, an infinity pool with a view of Siena, Happy Hour, wonderful breakfast buffet on their patio and super nice staff. It’s a relaxing, idyllic and wonderful place to stay.

Can’t recommend place we stayed in Montepulciano... it’s in Rick’s Tuscany guide, he raves about it... we did not like it at all.

Hi,
Roberto is giving you expert advice.
The other way to answer your question is to get hold of some travel books like Lonely Planet or Rick Steves on the area.
Siena is a lovely city, not huge , easy to walk in. It is not as easy to have a car but can be done. We paid a service offered by our bed and breakfast accommodation to pick us up and take us to our car as well as park it overnight and take us back to the B and B. Not cheap not hassle free but they were fast and efficient.
Montpulciano is a lovely town and would give you access to both Tuscany, and Umbria at an easier distance to drive. It would be easy to do a day trip to Siena from there too. I enjoyed our six nights in Siena last year and we made the car work, but really think about what you value and prioritize.
We expect to be returning this fall staying in Cortona this time after a visit in Florence again.

Thanks so much for such quick and informative postings! We look forward to anyone else's point of view. The Borgia G. listing does look very good.

the Borgia does look nice too, very nice.

You may want to rent a car at the Florence airport, or in town but ztl issues to learn about first, and drive down to Siena. But if you want to rent it in Siena the place we used is not to far from the Borgia. Europcar is on Aviana Europa. There is also an Avis over that way. Google maps.
We used the consolidator Autoeurope to reserve. Kimwei is another.

ttmom is right, car rental places not far from Borgo Grondaie, We rented one through AutoEurope as well our 2nd visit.

First time we stayed at Borgo Grondaie we weren’t planning to rent a car... they had a lot of brochures for guests in their lobby and one was advertising for a Smart Car rental... we decided to do it... they brought the car to us at Borgo Grondaie and picked it up there when we were done. It was not expensive. Have no idea if that service is still available but it was wonderful. And, loved the car!

PS the photos on Borgo Grondaie’s website don’t do it justice. Way more beautiful in person. Who took those photos???