I do think new members should have a mentor. There are many different aspects to the site that can be confusing as hell when you are new and muddling your way around. A mentor should have a rough explanation of each part of the site, the points--honest points vs. point farming--and work with their students on reviews. Of course there is always an exception...if the new reviewer is a very good to excellent writer and covers the review very well then they should find an experienced, long-term member to 'buddy' them for an explanation of the site and the different aspects.
If you are going to Mentor you should enjoy helping people, have patience, put yourself out there and be a good example for the students. If the points and gift cards are the primary interest--don't bother applying. I would rather have a point farmer than a bad mentor on the site. I know that sounds bad, but a point farmer is just a skunk--a mentor that does not care about working with her students is a dead, maggot infested stinking skunk.
It is the rotten, stinking one that does the most damage by graduating new reviewers too soon and allowing them to choose assignments, wreak havoc (unintentionally), and get all the benefits of an advanced reviewer without any of the knowledge of an advanced reviewer.
The cause of a lot of frustrations and irritations are people who do not know the policies, program details, about farming on the site and who cannot write a decent review. These are the ones who need our kindness and help. The mentors who are just greedy for points do not need any help---other than off the site.