The perceived warmth from an outdoor fire is dependent on the size of the radiant heat source and the distance from this source. Any natural breeze will effectively negate convective air currents from providing warmth. The size of the radiant source will be either the bed of wood coals, or in the case of a fireplace, includes the hot stone/brick work surrounding the fire bed (look at the Rumford fireplace design). The distance from the radiant source involves the inverse square law (double the distance from the source and the radiated heat drops to 1/4 of the original). Your choice becomes how many people can you get huddled around and how close to either a fireplace (not so easy/safe) or a firepit? Most would choose a large firepit. Notice that I left a gas firepit out of the discussion? Unless the gas flames can heat a bed of something to radiate, IMO, there isn't that much outdoor heating effect available from them., they are more for show.