Although freshmen classes are fairly large, each large class is split up into smaller groups for recitations with TAs. The professors also have reasonable office hours and will know your name if you frequent them. As you go further into the curriculum here, your classes become smaller and smaller and professors definitely know your name. Right now none of my classes are over 40 people. My favorite class is probably Graphic Storytelling, which I'm taking right now. It's definitely awesome to go to such a technologically-oriented school, because the professors tend to incorporate all sorts of materials and media into class lectures, which really adds to it all. My least favorite class was probably Calculus 2, which I'm awful at. The professor was amazing though - he really knows what he's talking about. If you ever get a chance to take a math class with Prof. Schmidt, definitely do it.
Class participation is varied, but pretty common, especially in the smaller, upper level classes that are major specific, because that's when you get into material that is appealing to you specifically. Students study pretty often, but it can be social as a freshmen because a lot of the core classes are the same, so it's not as much of a drag. RPI students do have intellectual conversations outside of class - that's what's so awesome about this college.
Students are varied in terms of competitiveness - there is the range of the very anal student who calculates their average after every homework, to the genius who does no homework, doesn't care about grades, but ends up acing the final without doing any work.
I'm a dual major in STS (Science, Technology, and Society), which is like sociology but applied to current issues and technologies, and EMAC (Electronic Media, Arts, and Communication), which is a digital art/communication major. Both of the majors have awesome programs. STS is a smaller program, with only about 5 people in my class in this major. It's really easy to fit in a dual major with this program, because it's so interdisciplinary and versatile. EMAC is a larger program, one of the only and most prominent art majors at RPI.
RPI's academic requirements have worked fine for me so far. So many students come in with credits from community colleges, APs, college courses from high school, that the curriculum is easy to mold to your specific situation. There are some classes that you can't get out of, but that's pretty unavoidable. RPI's education is geared toward learning, but also to the future and what you'll do once you're out of school. There are a lot of opportunities to network with alumni within your major, whether it's through a class project or extracurricular activity. There are also a lot of major career fairs on campus.