I had an amazing time in Mérida through this program and really improved my Spanish!
The opportunity to take classes at the local university (or universities) was integral to the significant improvement I saw in my Spanish and really allowed for a deeper understanding and integration into the culture. At the same time, the program classes give you a minute to step back and reflect in a more familiar environment. The program staff are also incredible and super supportive, so you always have a space where you can be comfortable sharing any concerns or issues you may run into.
As for living in Mérida, the host families are all incredible and really welcome you into their homes. Mérida is a beautiful and very safe city and I loved getting to know it throughout the semester. The surrounding area is also full of interesting and gorgeous places to visit, and the program does a great job of organizing excursions to expose you to different parts of Mexico and the Yucatan while also leaving time for individual travel.
Living in Mexico also gave me a totally different perspective on the relationship between our two countries that I think is really valuable and unique.
Overall, it was an unforgettable experience--the main drawback is how much you'll miss it when it's over (and yes, it is very hot).