Several people have asked me privately via email what I think of Butterfly Labs and ASIC mining in general, so:
What do I think of ASICs hitting the "mining scene" ?
meh.
It shows that Bitcoin is considered stable enough for a company to invest a LOT of money on design and production on it, which is very good. ASICs were bound to happen if Bitcoin survived long enough.
The long-term outlook for mining is "mining will happen with very specialized hardware, in places where either electricity is free or generating lots of heat is a benefit and not a cost" (and probably both; I still think Iceland will be a big mining hot-spot eventually).
I'm not worried about Butterfly Labs deciding to take over the blockchain with their superior hashpower. They'd be idiots to do something like try to mount a 51% attack-- they don't want to kill Bitcoin, they want it to get more successful so they sell more hardware.
And if they are successful they will very quickly have competitors.
Full disclosure: I spent some of my bitcoins to pre-order their USB coffee-warmer doo-hickey. It gets cold here in the winter.