We stayed at Casa Dos Lirios last month for our Christmas vacation, and could not have been happier. Sue and Steve are excellent hosts, going out of their way to make sure everything is perfect for your stay while also being mindful of your privacy.
We had one of the king rooms, which was spacious and tastefully appointed. There's a lush green courtyard adjoining each of the five rooms, providing an opportunity to meet and interact with other guests but big enough for each to have their own space. If you like the anonymity and privacy of a hotel room then this may not be the place for you, but it's great if you're a people person and like to chat with fellow travelers.
Location-wise, it's in a quiet residential neighborhood, walking distance from the main tourist attractions-- anywhere from 10 to 25 minutes. There is also Uber in Merida, if you prefer not to walk.
One of the best parts of our stay was the breakfasts Sue prepared each morning-- delicious! She makes an effort to adapt to each guest's dietary restrictions and preferences as well. On Christmas morning, we were treated to prosecco mimosas and Baileys with our coffee :).
Sue and Steve are also great resources for exploring Merida and the surrounding areas, with great recommendations for day trips and restaurants. Would stay here again in a heartbeat, and highly recommend for those traveling through Yucatan!