Are the practice exams in "The Real ACT Prep Guide 3rd Edition" easier or harder than the real ACT exam? Or are some of the questions too easy?
Since the ACT seems to be getting harder (particularly in the past 5 years), the pre-2010 ACT practice tests might not be as accurate. They'll still be good practice, but if you want to get the most accurate picture of how you'll do on the real ACT exam, make sure to take practice tests 4 and 5 in the Real ACT Prep Guide, 3rd edition.
The current ACT essay is also completely different from the practice tests in the Real ACT Prep Guide, 3rd edition. If you want to do practice essays, you should use the official ACT prompts that have been released online by ACT, Inc. We have both of these prompts (along with four others I constructed based on the prompts ACT, Inc. has released) on our blog, available for free. There's no point in doing the practice essays in the Real ACT Prep Guide, 3rd edition (unless you're bored and looking for an idea for an essay to write about in your free time).