Lüneburg is a quaint and historical city in Lower Saxony. It's medieval architecture makes you feel like you're in another time. This naturally makes it a bit touristy in the warmer weather, but it is a really cool town to explore. There are so many shops and cafes in the downtown area, it's fun to explore and wander. Public transport in Lüneburg is good, the buses are often and consistent, and completely free for student use. Students can also use their student pass to travel in Lower Saxony for free, so it's easy to take day or weekend trips to Hamburg, Lübeck, Bremen, and many other cities. It's location to the larger cities like Bremen and Hamburg make it easy to travel out of.
The USAC program is on the Leuphana Universität campus. Classes are only with USAC students, so there is some limitation there, but the staff is very helpful if you're interested in enrolling in a course with Leuphana. They also will personally set you up with a German language partner, likely someone who wants to learn English, so they're great to practice with. Upon arrival you're also given a German "buddy" to bring you to your housing and tell you a bit about Lüneburg, and so forth. Mine was very friendly and we got along well. She gave me a lot of useful info and hung out with us for the rest of the semester, but apparently some of the other buddies weren't like that at all. If you want to make German friends, you'll have to reach out outside of USAC on your own.
The classes themselves were great! I was in beginning German with no previous experience, so naturally it was hard at first. The language courses are intensive, so you're learning 4 semesters in 1. In the beginning I studied a lot during the week, but I had no problem traveling on the weekends. After a few weeks, things eased up so I had tons of time. As for other classes, some have a lot of work and some have almost none You'll get a good picture on the first day and be able to switch your schedule if you want. Also, Fridays have no classes, so you have long weekends to travel.
The staff at USAC is amazing, and they all genuinely care about the students. They are all Germans, so at first they can come off as slightly cold or overly serious, but all of the members of the staff there are actually really cool and interesting people. My German teacher was energetic and funny, he made long classes bearable. I had a class with Uta, one of the Assistant Directors, and she is an extremely sweet and caring person. I also had a class with Sören, the Resident Director. He is serious in class and expects students to do the work assigned to them, but outside of class he's really funny and relaxed.
Housing in Lüneburg is a bit more limited because it's a small city. There are apartments available downtown that are extremely convenient, I spent a lot of time in my friends', but they're also on the small size and landlords and roommates can be hit or miss. I had a host family, and I definitely would choose a family again. I had my own room, bathroom, and full access to the kitchen. My host mother was genuinely interested in my experience there, she invited me to eat with them from time to time, and we talked often (usually in German so I could practice) about what was going on. I didn't have any problems with privacy or independence - my room was mine, and I was able to come and go as I pleased. The only downside to the home stay was that it wasn't close to downtown, so I usually had to be back home on the last bus, or camp out at a friend's apartment.
All in all, I really enjoyed my semester in Lüneburg. It was a great opportunity and I met a lot of lifelong friends. I got to see a side of Germany that I would never see as a tourist, and I'm now comfortable enough with German to travel around on my own. I would suggest bringing some warm clothes though, it's really cold in the winter.