Stayed there a couple months ago. Overall pretty solid offering. Afternoon tea is not much to write home about but the evening drinks and appetisers are fine as a start before heading to any number of good food establishments on the same street. Breakfast is downstairs, not in the lounge.
Fun fact: The ownership also owns the Sofitel property around the corner. I usually do a night or two at the Mercure Soi 11 and then I book into the Sofitel. The Mercure is more than happy to shuttle you over to the Sofitel in their tuktuk for free ;-)