I use RoL for a couple reasons, i suppose. Although a 6/1 momentum'd BoL will add some damage, that's a momentum you would probably rather have on a 15/9 golem when a real shield pops up. Additionally, no opponent will ever use CC on your Rol, so you can put it out from turn one if you don't have a cremate and generally don't have to worry about it being taken down (unless you only have one of them and no cremates, then i'd save it in hand for sure). Also, if you have a clogged hand, you can't play a BoL and wait for a cremate, but you CAN play a RoL and leave it on the field for a while. I've only been in maybe one or two situations ever where the damage difference between RoL and BoL made a difference, so i'm going with RoL on this one.