Pretty much comes down to a few things.
Would you rather have +1D4 fire damage on each hit. Ontop of that, the everburn blade glows and casts a small 'torch' effect around you which can mean you are seen while sneaking.
Or rather +1 to hit and damage and 1 spell cast per day.
How usefull they are in the long run is hard to say. Theyre about on par with eachother id say. Do note though that fire is the most heavily resisted elemt in the game alongside poison, so over the length of a campaign id say the sword of justice has a slight edge. But the difference is minimal tbh.
