My apologies if you have already covered the subject, but ... what are your commits on the use of mining_proxy with the new ASIC boxes coming online?
And does anyone know if bfgminer supports the variable difficulty being talked about here?
My recommendation is to not use proxies unless you actually need them. Bfgminer has Stratum and vardiff support built in, so you'd be better off connecting it directly to the pool. But if you have multiple mining computers on a local network, you may save a little bandwidth by using a Stratum proxy instead of having each connect to the pool directly.