Anything is hard if you have absolutely no interest in it. If you love history, you'll do well in a history degree. That's why Oxbridge interviews people to see how much passion they have. With law, it's difficult to say you're passionate about something you've never studied.
In my experience, very few people were passionate about law. I think most people studied it because they didn't know what else to do, law was reputable or as a means to an end, to become a lawyer. I also found some people liked parts of it, and disliked other parts of it.
Law is often a dry, technical subject and I find it has more in common with computer science than an arts degree. For a degree to be qualifying there's not very much choice in the modules studied - only 5 or so modules over the 3 year degree are usually optional.
At a range of universities, 60-70% get 2:1s, 3-10% get firsts, the rest get 2:2s. Sometimes as many as 30% end up with 2:2s. In terms of classification it seems to me looking on unistats, law hands out substantially less firsts (which can reach 30-40% in many courses) and 2:1s, (which can reach to almost all of the people who didn't get firsts).
In exams, problem questions are often very difficult to get firsts in, unlike essay questions - in my experience.