Choose free-standing when there’s no wall where the footfall is, when the venue bans fixings, or when the sign has to move between events. Choose wall-mounted when the position is permanent and you want it flush and out of the way.
Most exhibition halls, listed buildings and hired venues won’t let you drill, which alone settles it for a lot of buyers: a Bespoke LED Standing Light Box at £99 stands anywhere with a plug and needs no brackets or making good afterwards. Where the spot is fixed and depth is tight, a Bespoke Ultra Slim LED Advertising Board at £55 sits near flush and keeps the floor clear.
The deciding question is simple: does this sign live in one place forever, or does it travel and change setting? Travelling or temporary means free-standing nearly every time. Compare both lit on a free mock-up before deciding.