Just back from 5 days at the Relais Santa Croce. This is a superb proper 5 star hotel. The Hotel itself is very well situated just outside the very hectic and packed touristy area - about a 2 or 3 minute walk and you are in the thick of it. The Hotel itself is a beautiful palazzo - if I remember correctly - built by a former treasurer to a Pope. The common areas are exquisite and almost a "sight" to see in their own right. The staff are very helpful and accomodating. The restaurant in the hotel is superb and service from Samuele excellent. I suppose one should really venture out and try different places to eat but the food was so good we opted to eat in most evenings. (A word of warning - there is a 3 star Michelin restaurant in the hotel - but NOT part of the hotel - suggest before you rush off there you look at the reviews on Enoteca Pinchiorri before booking)
The rooms themselves (we had a junior suite room 202) are superb and every evening there is a nice touch of fruit/cake. The rooms are in keeping with the character of the hotel but fully modernised eg the air conditioning actually works well.
The hotel is quiet and perfectly suited to couples looking for a few days rest and realxation but also wanting to see all the art and culture that Florence has to offer. The staff are very good at assisiting with any queries and nothing seemed too much trouble at all.
We have already decided to return next year and have convinced our parents to stay. For the first time on Trip advisor writing a review was hard on the basis this is such a great place we selfishly wanted to keep it to ourselves.
A small tip - there are hundreds of restaurants around the many squares. We ate lunch out every day and would really recommend the Circus restaurant which is nearby - I am sure the team at RSC can direct you