I did one on the GroundCntrl app. It was easy, albeit a little awkward. You had to snap specific pictures of shelves and different areas, and the restaurant I was in wasn't crowded at all so I felt a little exposed. But it was very easy. I did not have to upload a receipt. However, I believe I was doing a test for the MSC, so they may begin to require it, not sure. They also now require the shop to be done during very specific times and days, which don't work as well for me, so not sure how many I'll do in the future.
I should also add that I performed the job two weeks ago and was paid today. Gotta love this MSC!