I stay in the Mercure several times a year when I am working in the Cannes area, it has good parking which is a bonus and is easily accessed from the A8 motorway, staff are always helpful, room service menu could be a bit more varied, but restaurant food is good as is breakfast. Rooms are nicely equipped with comfortable beds.

Recently stayed at the Mercure for a couple of nights during a business trip. The room was comfortable and had everything I needed, including in room WiFi which meant I was able to keep working once getting back for the evening.

Staff were also friendly but this hotel is a little outside the centre of Cannes so you will need a car or taxi to get into town.

Everything about The Pullman has all the marks of a good hotel. Good attentive staff. Excellent front desk. Good size rooms and great views. A restaurant which produces good food (although not always consistent), so that it's not always necessary to hunt for outside restaurants. A clean and good size swimming pool. Plenty of room to soak up the sun but put a towel down early for your preffered sun loungers.
Good outside bar and menu but sometimes under staffed. Probably one of the best views and position of any hotel in the South of France.
We parked our hire car on the road ouside the hotel. The charge for valet parking is 12 euroes per day.
The one BIG problem that this hotel has is that they have seminars and conferences and private functions. To my mind this is not condusive to a relaxing mix staying in an expensive hotel. We understand that times are difficult and it is necessary to maximise turnover but is it a hotel or a conferrence centre with rooms? The design and the build of the hotel means that several of the areas are shared by paying guests and various seminar / conference groups.
This doesnt apparently cause a problem in high season, July and most of August.. but we were really affected for three nights and to a lesser extent during the day... out of the seven days we stayed at the end of August/early Setember.... by a group of approx hundred people for a four or five day seminar.
We had to call a meeting with the manager one morning who in fairness dealt with the lack of control of the previous nights, after our meeting.
It is a good place to stay but DO check what is happening ie events etc during your required dates/stay, so that you do not have the problems that we had.