Should I become a reviewer for Math Reviews after leaving academia? After finishing my PhD in mathematics not long ago, I decided to move away from academia and pursue a career in the commercial sector. I'm currently not affiliated with a university. In the long run, I might return to working at a university some day. 

Recently, I recieved an invitation to become a reviewer for Mathematical Reviews. I'm flattered, but also hesitant as I can't fathom how much extra work this will be and if there's a benefit for me, besides learning more interesting things in my original academic field of expertise (which I've moved away from a bit).


How much work is it to review 1 paper per months, roughly speaking?
Would you see being a reviewer as an interesting CV item outside of academia?
Doing the reviews is usually not paid, correct?


This question is similar to Should I agree to review papers as a postdoc?, which didn't give me quite satisfactory answers since I'm not in academia anymore.  It is also similar to Personal advantages of being a referee once you quit science? but that one is not about math reviews, which are different from refereeing a paper for a journal.
I'm a reviewer for Mathematical Reviews (now best known by its association with MathSciNet).  My experience has been:


I usually spend about 1-2 hours to read a paper and write the review.  

I don't necessarily look to completely digest all the details of the paper, but I at least try to understand what the results are, why they are interesting, how they relate to previous work, and a general idea of the proof techniques. 

Note that, unlike the pre-publication peer review process, you're not expected to check the correctness of the proof, nor to make a judgment on the paper's novelty or significance.
They want you to submit your review within about 6 weeks of being invited.  
You can set your "queue size", i.e. the maximum number of papers you want to have at any one time, to whatever you want.  When you submit a review, you can expect to receive another invitation within a few days.
You can always decline a review invitation if you are temporarily too busy, or if the paper doesn't interest you or fit your expertise, and they will just send it to someone else.
You can specify your areas of interest (by MSC code) and they send you papers that appear to match your interests.  If your interests shift, or if you start getting a lot of papers that mystify you, you can make changes.
It's a very minor CV item even within academia, and probably even less outside.  
You do get a little bit of extra visibility, since reviews are posted with your name, and seen by anyone who looks up the paper on MathSciNet.
You do get paid, sort of.  You receive 12 AMS Points for each review you submit.  Each AMS Point is worth $1 (USD) in credit toward purchases from the AMS (books, journal subscriptions, membership fees, etc).  So it maybe adds up to a couple of free books per year.
Also, if you review a book for them, you get to keep it.