Overall I had a great experience. The city was beautifull, the people were friendly, and the school was great. I studied at the Universidad Pablo de Olavide and my professors were really cool. They understood that we were not studying abroad to do loads of homework so the work they gave was reasonable. I had a lot of time to travel to other countries in Europe as well. The night life in Sevilla was great. There are a lot of fun clubs and bars around the city, especially on Calle Betis (I'm sure you'll hear this name plenty of times when you go). The city is also pretty safe. My friends and I were never harrased or anything and never felt unsafe walking around at night.
The food took some getting used to--they use A LOT of olive oil for everything.
The program itself is pretty good. It was much smaller than the other ones and you are expected to be more independent. You have an Adelante staff member in Sevilla in case you have any problems and other then that you pretty much do your own thing. I chose this program because is was the cheapest--while many of the other programs organized trips and sometimes different events for their students, they also cost much more $$. I prefered saving a few thousand dollars and planning my own trips to the places that I wanted to see. And you will always find people at UPO who are ready to travel with you.
I would reccomend this program to anybody who is independent, ready for a huge growing experience, and doesnt mind not having their hand held while being abroad.