The city: It has a beautiful big castle and it is on the coast. Although the main beach is not super gorgeous, if you take the TRAM just a few minutes north, there are some incredibly beautiful beaches that will astound you (ex. Cabo de las Huertas). The climate is somewhat similar to So Cal weather but the summer is hotter and more humid. The center of the city is small and the area where all the bars are is also pretty small but it is in the coolest old part of town. Alicante is a tourist destination, it is not very authentic Spanish culture if that is what you are looking for. The city is really safe, just have to watch out for thieves like in all the rest of Spain.
Big plus about the city: it's cheap!!!
Social scene: Lots of students! Most from all over Europe, but not necessarily Spain. If you come to Alicante to study, it can be tough to find Spanish friends because there are so many exchange students, but I would really suggest to make it a priority to speak Spanish while you are here! Don't just stay in a group with Americans the entire time. The nightlife here is fun but it might feel monotonous at times, especially since most places play the same type of commercial music. That's why you have to travel to experience more diversity!
School: Depending on your subject and luck, classes can be really tough or easy. Your level of Spanish should be really good but it does not need to be perfect. Good news is teachers are generally more lenient with the exchange students, especially if you speak with them one on one. Do not expect to get straight A's here and expect to study.
If you come here, be sure to TRAVEL around Spain! Alicante is small so traveling on days off of school is the best thing to do and traveling is cheap!! And Spain is SO amazing, every city is different.
My experience has been great. I met friends that I know I will have for the rest of my life and I've seen places that are incredibly special here in Spain.
Traveling abroad is what you make of it....it can be the best time of your life, it is mine!