USPS shop guidelines are clearly written. Although it looks like 90+ questions on the evaluation, it only takes me about 10 minutes to complete the report. Very straight-forward and the only narrative is if something extraordinary happens. I count them as super-simple.
Fast food, also very simple.
I found the oil change/car service shops to be well written, easy to follow, and simple to report. I drive so much I qualify for an oil change about every other month; love getting something I need and getting reimbursed for it! In my area, they also pay $25-$30. There is more narrative involved, but not an overwhelming amount. Several timings, descriptions, and names required.
Banking can range from simple and easy inquiries to long, involved discussions about planning for retirement.
They range from $15 to $250. Obviously, the $250 shop is NOT for beginners! Heavy narrative requirements.
Automotive dealers, depending on the MSC, can be easy or impossible. I personally find some shop guidelines to be so poorly written as to be confusing and difficult. Others are so clearly written and easy to follow that they are a joy. Some companies give new shoppers "sample narratives" -- if you follow the structure of the sample closely, you'll be a rock star. I would overall state, though, get some other experience under your belt before attempting these.
You get into fine dining/hotel/resort, expect HOURS of detailed narrative. Not for the newbie -- too much at stake if you goof and your report is not accepted.
Apartment/senior living (I know, you didn't ask!) can range from difficult to impossible. Not for beginners!
Some companies, if you're upfront with your scheduler that "I'm new, I might have a lot of really dumb questions", will say "we'll walk you right through it" and be encouraging and positive -- those are the ones you want to do your best for. Others will throw you under the bus.
I personally don't like doing many different types of jobs in one day. I might do 3 banks today and 5 gas stations tomorrow, and 3 fast foods the next day. Other shoppers do 17 shops in one day, and mix them all up. I couldn't possibly keep that many different types of shops straight -- I'd for sure screw up some of them. Especially if several of them were "new to me" shops.
That being said, today I'm doing one gas station, one price audit, and one fast food. But they are all shops I have done before and I'm extremely comfortable with all of them. And since you didn't ask, I'll tell you -- I'm
getting $110 for the audit, $125 for the gas station, and $50 for the fast food, so I will make $285 plus reimbursements for my 8 hour day.