Both of these hotels are on the Promenade des Anglais, so very good location. I know some-one who stayed at Le Meridien and enjoyed it. I think they said it has a roof top pool. We actually stayed in a privately owned apartment in the Palais de Meriteranee building and found it extremely reasonable/convenient and of a very high standard. We had never done this before & enjoyed the flexibility it offered. ( But no swimming pool)
I don't think you'll go wrong with either of the hotels, but if you want more info please ask or PM.