PRO: You get to read the book before it comes out.
I think this is by far the biggest PRO from this whole list. It's one of the main reasons we usually read ARCS. Sometimes we can read and review it for an author to make miniscule changes before publication, other times we get the opportunity to promote and spread the book around. While you may not have many people to discuss the book with, you get to go into the book with a clean slate, no hype or expectations.
CON: You'll probably have to wait longer for the sequel, assuming it's part of a series.
Unfortunately while you get to read the book earlier, usually the second book isn't available as an ARC and the waiting period between the first ARC and the official release of the second book is longer than the period between both publication dates. Essentially it's just a few more months of waiting.
PRO: ARCS are usually free.
Another big pro is that ARCS are usually given either by the author or the publishing company, so you don't spend as much money on books.
CON: Most likely, you'll get the paperback version.
Since you aren't sold the book, you don't get a choice on the format. Usually the book is paperback and sometimes it doesn't even have a cover.
PRO: You get the opportunity to network
Like I mentioned earlier, ARCS are usually associated with authors and publishers, people who are influential in the publishing business. Reviewing an ARC for a publisher tell them that you would be open to reading more books from them. Not only does it help them promote their book/ company, but it helps you promote your blog. It's a win win situation for everyone.
CON: Sometimes authors change things between the ARC and published copy.
There are many times when the author of an ARC has emailed me and told me they took some of my thoughts into consideration and changed minute details within the book. I find it amazing that I have any type of influence on a book and I really want to read the changes made to the book, but I usually don't have time to reread the entirety of the book.
Generally I love ARCS. For me the PROs completely outweigh the CONs and I love getting ARCs, so much that I usually promise reviews to more people than I can handle.
What do you guys think about ARCS? Hate them, love them? Let me know in the comments below!