Flavor wise, assuming you have close to the same build is there any differences between the igo bf and the RM2?
For me, the RM2 provides better juice delivery.....the feed/return hole is IN the base, and larger than the IGO-S (the -S has the feed/return hole drilled in one of the posts -- and it's tiny, compared to the RM2)....
I also have found the IGO-S seems more prone to flooding if you're not careful with your "squonk"!!

End of the day....BOTH RDAs provide good service on the Reo.....and, yes, I do use the same coil build on both -- 1.2 ohm single micro coil, 30ga. kanthal wound on a 3/64" mandrel, cotton wick/cloud combo....
Good luck!
Happy(vaping) Trails!