For me, Sentry has been good. It's one of the longer MSC I'm still with when I started and have a good presence in my area. I did a good number of shops to try different clients. In my area, the clients have mostly remained the same and haven't done as many shops with them lately. However, I've had worthwhile shops with them, as well. Overall, I felt that the editing team was patient and helped me early on with the type of reports that the MSC seeks. That's been one benefit of the forums, reading past threads and posts. But at least for me, my interactions with the MSC have been professional. However, I believe this was after changes were made to the MSC. From other shoppers in my area, they've had similar and positive experiences.
For Coyle, it comes down to the report versus the value, if it's worth it. Also, any reimbursed amounts you have to front. In that way, I get why it's going to be at the bottom of the list, and it's going to be a smaller pool. Even though I haven't been with this MSC long, I can say I've had a positive experience with them, to be worthwhile to me. In terms of overall value and reimbursement amount, it's by far the highest with the hotel and fine-dining shops.
Merchandising in general - I haven't looked into or pursued. I don't know if I would really be effective and efficient at this. I think I would have to glean from others or go through a lot of trial and error. For those who do it regularly, I think they've got it down, but it would be a learning curve for me.
Confero - Used to be active, but not as many clients before.
The Jack Network - Lost a bigger client and a local client. To me, I had a good working relationship with KSS. But no more shops in my area that I would be interested in.
Trend Source - Used to offer sizable bonuses for grocery store. Only did the grocery store shops.
Regal Hospitality Group - Considered a hotel shop, but after reading charlhenri's experience, glad that he posted.
Second to None, BestMark (CX Group) - Outside of grocery shops, took a break.
Market Force Information - Select shops every once in a while. But may ask to do the burger and chicken finger shops again! For other reasons.
Also, I've been making a list of MSCs I've been meaning to sign up with that others have recommended, but may not start until next year.