I can't say i know if it is easier or not but personally RC has one difficulty. If you are able to read a research article quickly and retain the information then RC should be easy. If you read through an article and have to look back to search for the answer then it will be hard.
Regardless of the book you are studying from you are practicing whether you can retain the information you just read.
I personally did not study the RC section at all. Like 0% percent. To me there is no good study strategy for RC because the answer is literally right in front of you. When i took the real exam I did not read the article, I went straight to the questions then looked for the answers.
Remember this is solely my opinion. I'm sure someone else would have better advice than mine :O