This depends on which part of the garden you wish to add a glow to:
Standing: the most practical, portable and versatile! They'll become the center of attention if you place them on a table, or create a virtual bubble around you and your guests when the sun goes down if you leave them around the seating area. If you haven't already got any permanent garden lights, you could use standing lanterns to illuminate the walk from the gate to your main door. They'll also allow you to get creative trying different combinations and layouts whenever you fancy a décor revamp;
Hanging: because they need to rely on some kind of hook, these outdoor lanterns are a bit more restrictive. However, they could still be a better choice if there's a specific spot in your garden or patio that should always be illuminated, especially if the lighting above your table and chairs isn't bright enough or, on the contrary, is so bright that it ruins the atmosphere: hanging lanterns will create the perfect balance!