Small classes are definitely a major strength of academics at Bryn Mawr. The size of the school is about 1300 or so, and that's just about right for me. It makes it so that even introductory science lectures, which are the largest at any school, have less than 100 students in them. The biggest class I've ever had was Environmental Geology freshman year, and it had 80 students despite being capped at 40, but the professor changed the lab schedule to accommodate everyone. The small classes are great, although lotteries can be frustrating, and everyone tends to be eliminated from a few classes while here, but luckily there are enough good classes that you can find something else, or talk to the professor if you really want or need the class, and they will often let you take it.
After you finish these introductory classes, most have fewer than 20 students. Professors always know your name, especially in major classes, and discussion is the norm, when appropriate. Many majors have very close student groups, which is nice and makes classes much more comfortable. As a geology major, I can tell you that it is an excellent department. It's really close and has a strong sense of community. There are four permanent professors and few part-time lecturers, lab professors, and emeriti professors. The professors are all excellent and are real experts in their subject areas, and students are challenged to engage with the material and really understand how different processes work. This kind of dedication and quality are characteristic of most departments on campus, and the classics, archaeology, computer science, geology, and chemistry are particularly highly regarded nationwide.
Outside of class, academics still tend to dominate. People spend a considerable but usually not unreasonable amount of time preparing for class, studying, or doing homework. Most weekends you can spend Saturday not doing work for classes without any problem. People are very interested in their studies here, though, and this comes out in conversations and Mawrtyrs' view on the world. People are interested in doing something truly meaningful with their life after college, and so while many students tend to have one eye on the long-term, that trajectory is formed by academic and social passions. A Bryn Mawr education prepares you for that world by teaching you the knowledge and fostering a sense of curiosity and confidence, because you know what you're doing.