Pretty sure on average Oneth's will give you more DPS in ST and it sure as hell will in AoE. In addition, it makes your incredibly garbage 0% DPS for AoE 2P and 4P actually worth a damn. That said though, I have OI and PoE (also a few garbage legendaries like Sephuz and Shittidaria), but I prefer the boots over them because of the emergency heal it provides. It's saved my group from wipes so many times when I just have an emergency heal ready.
That said, PoE is definitely more consistent than OI. It might worth using in pure ST with low movement (OI+SD = better for movement even on ST; e.g., I'll always use SD on Trilliax for the mobility it gives during lasers) if you want the consistent damage, though when OI procs like mad, it's so fucking satisfying.
Also another small consideration for PoE is that it's a boot, which has more stats than OI which is a bracer (also PoE has BiS stats; OI has kinda close to BiS).