I've had Mystery Guest, Inc. on my to-blog about list for several months and I'm excited to tell you about this company. I have completed several shops for them (for me, their only shops are a big name "chain" of restaurants that most everyone I know LOVES) and find their reports to be very straightforward without lengthy narrative.
They pay with giftcards though - so the first shop you do you'll pay for the food and then receive a giftcard for the restaurant. You CAN use the giftcard on subsequent shops so I roll the giftcard like it's ECB's! I'm serious!
Anyway, Mystery Guest, Inc. sends an email out once a month when they release new shops and if they don't have the dates you want listed just shoot them an email with your availability and they will try to accommodate you.
Once you've signed up it may take some time to be "accepted" - they'll accept you pretty quickly if they need shoppers in your area. If you don't hear back from them within a few weeks, you can always send an email just letting them know how interested you are in shopping with them. They have been a super nice company for me to deal with.
As always, it's FREE to sign up to be a mystery shopper for any of the companies I blog about. You can read more about the mystery shopping companies I blog about here. Please read my Mystery Shopping 101 post for more information.