There's something different with BFGMiner (all builds).  It can work fantastic on some pools, probably most pools.  But, on some other pools, it doesn't perform as well as CGMiner.   It could be problems on the pools.

I left 2 BFGMiner instances and 1 CGMiner instance running today on the same pool (3 Fury's).  I came back to a "wall of rejects" on the the two BFGMiner instances and both miners were temporarily banned from the pool.  The CGMiner instance was still running ok.