Hmmm good question. I think with Restaurants, as well as any big company, it is important to view how much of the price or value of a product is due to its marketing. For example a Nike shirt has billions of marketing dollars put into building a name brand, thus giving the impression to people that it's better than other lesser-known branded shirts. Thus we can take that analogy towards restaurants and view the branding, environment, and service as being the real difference makers.

Anyways I kinda got sidetracked there, but getting back to your question about food preparation. I think most restaurants have similar methods and sources of obtaining the food, as well as storing them, but the actual cooking/preparation might differ but more so on a taste/quality level and not so much as the macros. This is especially true for meat products because they require the most preservatives to retain freshness, and the longest road from initial grazing/feeding of the animal to being shipped to the restaurant and stored. So a vegan choice would be my way to go (I'm vegan FYI), especially at restaurants that usually store foods for longer periods of time than the average person IMO.