Hi,
Have had stays at both the LM & Sheraton, during the past month.
I'd say the rooms at the LM are average, as the property is quite old.
As a plat, I got upgraded to their Presidential Club and the only advantage was complimentary internet access in the room. The nice surprise was they gave Hermes soap & cologne as complimentary toiletries! As well as welcome fruits & chocolates! As mentioned, the club lounge on the ground floor is very nice and very French!
The Sheraton looks better but they lack a lounge, but make it up with a cocktail hour (6-7pm ??) at the main lounge. Was once upgraded to their "Casablanca Suite" and another to their "Poolside Room". Service has been excellent on both occassions.
I would stay at the LM for its location and number of places to visit. The Sheraton would be the choice if you like great service in a more updated environment.
Cheers!