I stayed at two Mercure Hotels:
the Mercure on Soi 11
and the Grande Mercure on Soi 19.
There are a number of Mercure hotels in BKK, and it is one of the best hotel chains I have experienced.
Staff are well trained, attentive, helpful, flawless, actually, and the rooms are unusually large.
The Grande Mercure rooms are almost too big: this is a serviced apartment hotel, with staff in the.
lobby, but the room is essentially just an apartment. Good quality everything, with a good kitchen, washing machine, bathtub and 2 excellent TV'.
I actually preferred the Mercure Hotel on Soi 11. It is more of a proper hotel, and is impressively furnished and spotless. The Soi 11 location is closer to Sukhumvit; the Soi 19 is past all bars, restaurants and hotels on that street. It is an old building, but classy. Oddly crowded traffic in the area, as there is an intersection next to the hotel that has constant traffic flow. As I was preparing to leave for the airport, there was such a traffic jam that I thought I might miss my flight: waited a half hour for a taxi to come, not because the staff did not try, but because traffic was completely stopped in all directions.
When I return to BKK, I'll stay in the the Soi 11 Mercure. It is the best hotel I have stayed at in BKK in some 20 years of visiting.