One of the main things you need to consider when deciding between a tabletop patio heater and a full-size fireplace is the size of your outdoor space. If you have a large patio or deck, then a full-size fireplace would be the better option. But if you have a smaller space, like a balcony or porch, then a tabletop patio heater would be a better choice.
One advantage of a tabletop patio heater is that it can be used on a table or other surface, making it more versatile than a full-size fireplace. Another advantage is that they are relatively compact and can be easily moved around, making them ideal for small spaces.