I've had good luck with Goodwin. I like their shops and I like that they use ISS which I find very user friendly and easy. It's a huge time saver. That said, companies are different. My first one I used was Goodwin so their style is what I know. I later did shops for Sentry and they told me, "Even if it sound redundant, you need to verify the question." So for example, if the item asked, "Did the representative offer you an espresso or water" and you check "no" in the text box, Sentry wanted me to restate it. So I literally had to go down the list and say, "No, I was not offered an espresso or water. Yes, I was shown to the door. No, I was not asked if I had been there before.."
You get the picture.
But then another company I worked with, that I did the same thing in the answers, HATED it. They emailed me and said, "Please don't restate the question. Provide more details if necessary but if you are going to add comments, please add something new." Or something like that.
My point. You may have got into a certain style of reporting that one company liked, that another company didn't like. Clients are going to like different types of reports, so there are different secret shopper companies. Very unfortunately, you also have to adapt to the different companies requirements. To avoid this, I just stick with three companies that I like, because the learning curve is steep and I don't want to risk not getting paid. My favorite companies are Goodwin, Intelli-Shop, and A Closer Look. I used to like Bestmark but they are all car dealerships now and I'd rather kill myself than go anywhere near a car dealership.