First of all, let’s address the fact that in the grand scheme of things, the difference between MIT and UCLA is marginal when it comes to computer science. The United States has something like 3000-4000 colleges and universities. If you look at the U.S. News rankings, MIT is ranked at #3, with a total score of 94 out of 100; UCLA is ranked at #19, with an overall score of 82 out of 100. There aren’t any good undergraduate CS major rankings for a variety of reasons, but there are probably like 100+ doctoral programs in CS. At the graduate level, both MIT and UCLA are in the top 15 or so for CS.
So speaking on a broad scale, the differences between MIT and UCLA in terms of educational quality and prestige are pretty marginal. They seem large when you are only looking at the universe of uber-competitive schools, but in the grand scheme of things? Not so much.
Unlikely. The undergraduate computer science curriculum is fairly similar at most schools, and both UCLA and MIT are big enough to attract researchers doing cutting-edge research in the field who will also largely be teaching classes (or at least influencing what the department teaches to some degree). If there are any differences, it’ll likely be in elective classes or special opportunities (like research, independent studies, special seminars, extracurricular projects, etc.)
Not necessarily. There are lots of things that influence the difficulty of a class, especially the difficulty to an individual student. One example is that MIT only has 4,600 undergrads, whereas UCLA has 31,000; your classes will almost certainly be larger at UCLA (especially the introductory ones). Some students may thrive in larger lecture classes and some students may need a smaller environment.
I wouldn’t necessarily advocate for an undergraduate student using the bios of professors and graduate students to determine where to attend. Aside from the fact that undergraduate education is a holistic experience (you don’t spend all your time in one department like a PhD student), at that point in time your academic interests aren’t fully solidified yet. They shouldn’t be - unless you are an unusual high schooler, you don’t yet have enough domain knowledge to know what deeply interests you on the level that would allow you to make such decisions. You may have some vague notions (like AI/ML or robotics), but not only are those probably covered at most schools with good CS departments, they’ll probably change a lot.
The professors’ research interests really mostly impacts the electives and upper-level courses that are offered, and you can determine whether those seem interesting by leafing through the course catalog.