It appears the BFGMiner definitely has better performance in terms of what it's reporting to the pools, but it's still a bit slow.
Within the miner I'll get 660-680 MH/s, but only about 580-600 are getting reported by the pool.
This is observed using MacMiner 1.3.17 (which may not be the latest build or official release version).
In MacMiner, the FPGA/ASIC miner works great except that every once in a while it'll just stop. I can set up a notification for idle workers but it always happens when I'm at work and can't take the hour round trip to restart the buggers.

Hopefully the BFGMiner will run with greater stability, even if I'm losing several dozen hashes/second. Better that than huge swaths of downtime.
Hey, interesting to hear about the different hashing rates, is this with ASICs or GPU mining, and what rates were you seeing with cgminer?
The 1.4.6 beta version of MacMiner updates bfgminer to a version slightly newer than the 3.1.3 release (as a few bugs were fixed afterwards) and BFG Miner and FPGA/ASIC Miner should automatically restart if it stops unexpectedly. Please give that a shot and let me know how it goes for you!