Although opinions vary depending on who you ask, it seems like all of my friends (everyone from engineering majors, to English, business, history, education, math, music, etc.) agree that the work is rigorous here, but definitely not impossible. I can back that up with my own experience. I have a few easy classes each semester, but usually at least two that take a lot of studying. Most students take 15-17 credit hours each semester (like 5-6 classes, depending on what they are) without getting too overwhelmed.
I'm a Food Science major, which is within the College of Agricultural, Consumer, and Environmental Sciences, or ACES. It's a mix of a lot of chemistry, microbiology, and a bit of cooking, statistics, and physics for good measure. My most challenging class has been organic chemistry, although physics and calculus were no picnic either.
My most unique class so far has been Indigenous Governance which I took through the Campus Honors Program as a Non-Western/Minority general education class. It was so much reading, critical thinking, and writing, but I learned a lot and I think I gained a lot of perspective about past and current Native American issues.
My favorite current class is Food Chemistry, but probably not a lot of people reading this will end up taking it unless you decide to become a FS major like me.
In terms of the structure of classes and the availability of professors, it is a mixed bag. 90{4a082faed443b016e84c6ea63012b481c58f64867aa2dc62fff66e22ad7dff6c} of my classes are fairly small (about 20-40 people) and I know my professors pretty well. Starting out, you will probably have some very large lecture classes, especially if you take entry level Econ, Chem, Bio, History, or Calc, but these are not as scary as you would think. Really! Big classes (I'm talking 200-500 students, here) are a lot of fun. You are getting the same lecture regardless of whether the professor is talking to 20 people or 200 people, and it's not any more distracting being in a lecture hall than being in a classroom (unless you bring your laptop and get on Facebook the whole time, which people totally do...don't be one of them). Also, most of the big classes divide up into small (15-20 people) discussions at the end of the week so that you can actually interact with the other students in the class and dive deeper into the material.
My Calc class freshman year was a good example of this. We had lecture 3 times a week, and then we met in discussion and did group worksheets and quizzes as small sections. Our TA was nuts, in the best possible way, and we all became good friends who studied with each other outside of class and helped each other with the online homework. Never underestimate the power of a tough class to bring people together! Also never underestimate the power of asking for help. Professors are required to have office hours several times a week, and they are often just sitting alone in their offices, wishing a student would come ask them a question. Take advantage of those opportunities to get to know your teachers! My calc professor saw me last year in a Pilates class and still remembered me from those times I sat on the floor of her office while she explained tricky homework problems. If you need help, seek and ye shall find...
Finally, it's one of those stereotypes of college that people sit around late at night and have highly philosophical conversations about life and politics and race and religion and identity and all that lofty stuff. Well, I can tell you that I've definitely had a LOT of those types of conversations in my time here. It's an amazing experience. If you have the right kind of friends (aka the best kind of friends ever), this can be a daily occurrence. Then again, if you hate that kind of thing, there's plenty of people here who hate it too, and that's okay. Different strokes for different folks. I'm ending this answer before I throw in any more cliches.