i prefer and use IOC regular diesel, makes engine noise reduce with good FE too.Also have heard Shell regular diesel is good as well but with some premium pricing and also increases engine noise, so havent tried.IOC all the way.
I voted for IOC. Though i've selected the station not because it is IOC, but because of the management. It is managed by a social service organisation and is the natural choice for many. You can always find a big queue in that already big station. And they give nitrogen gas for me. What else?
I prefer Shell followed by IOC.
The prices of IOC Extra Premium and Shell Super Unleaded do not have much of a difference (The Shell Filling station is located in SEZ, hence price is less ). There are has been a noticeable increase in the FE of my Bike on using Shell so I stick to that.