Stone Edge is honestly unreliable(its like Focus Blast, you stick it onto the Pokemon because there simply isn't something better to use)
Standard Tran runs Flamethrower/Fire Blast, Earth Power, a HP of your liking/Dragon Pulse and Explosion. And unless you explode on something that is bulky(Blissey/P2) Explosion > Stone Edge.
Assuming ScarfTran, Explosion will always KO after Stealth Rock.(Honestly, if you run Ulgamoth without spin support I laugh). Explosion does 78.8%-92.8% on Ulgamoth, meaning that with a layer of Spikes Ulgamoth still lives in its dying breath(which could be bad for sets running Swarm). That amount of HP means Ulgamoth dies immediately to a strong priority attack like Luke's ExtremeSpeed.