Over all I like to post reviews on Hotels and Restaurants mainly.
However, my favorite activity as a Local Guide is to Add a missing Place / Removing Closed Place, Edit the timings and Correct the position of the places. Due to high coverage of Maps, chances are less but whenever I see the possibility of it; I do it without fail.
Also, whenever I stay in any Hotel; I would like to put a detailed review regarding its Rooms, Food, Locations, Staff behavior, etc.
Sometimes, the place is having some unique offering, i.e. Best Pizza option, best cocktail available, best food item, best type of room, best place to click a photo for tourist destination, happy hours, etc.
It is always these unique things makes the difference to the place.