I have added Liqui Moly MoS2 to my cheap bar and chain oil and didn't notice improvement. I thought that the additive would reduce the friction between the hardened steel chain and the aluminum bar but I noticed no reduction in heat.
By far the best bar and chain lube I've found is Amsoil's Bar and Chain oil. I don't know what's in it but this stuff clings to the bar like tree sap and keeps things running noticeably cooler than any other lubricant that I've used. I think that the heat is generated between the wood and the chain with the secondary frictional loss being the bar/chain interface. So the bar oil has to cling to the chain and be viscous enough to absorb the heat generated before being flung off.
The only complaint I have, and this applies to everything I have previously used from Amsoil, is their price increases that have made it unrealistically expensive. They charge $23.39 for a gallon of bar oil and that's simply overpriced. Add on their $9.99 shipping for orders under $100 and that brings the taxable total to $33.38. Add tax on top of that and you're over $35 for a gallon of bar oil that will be consumed in one day of wood cutting. (sorry for the rant, I'm a bit disappointed)
So yes, I have tried MoS2 in my bar oil and all it did was make a mess with no notice of heat or wear reduction.