My account with them is not active, but that's only because I can't afford it right now. I really like SS, and hope to get back with them soon. I found links to shops with them that I didn't find on other MS forums. So many people claim they are a scam when in reality 1) They didn't read the site thoroughly, and thus missed the part that yes, you will be charged after your trial period, and 2) SS is not a mystery shop company,but a job board. You're essentially paying them to sort and organize this information for you.
I recommend doing the trial run, and if you find SS is not for you, then you're only out $5.00. If you're hesitant about using your credit/debit card, then do like I did- buy a reloadable debit card (which you can get at any drug or discount store) and use it instead.