what OS? if windows or linux have you considered Oracle Clustered file system? Are you implementing rac/ops?

A little bit of learning curve with raw devices, also consider the following
> You better have your storage planning/forecasting nailed. No resizing of a raw device like a cooked file system datafile. I know in windows on rac and ops if you need to add a raw device on the fly
you have to reboot all nodes of the cluster for the raw device to be seen
> You can't backup directly to tape with raw devices unless you use rman or export. If you are strictly copying datafiles as part of B&R you need to copy from raw to formatted file system and then to disk.
I would suggest RMAN.

regards

steve