If I were you I would not go with Butterfly Labs.
I placed an order with them, US$650, that for me was a fortune at the moment, and still is.
They just keep saying "we are almost shipping now". At this point I wonder if it is a scam, it might be.
Or just plain not understanding of what bitcoin means and how it operates. With such a bit delay, if they ever ship, they will be much much worthless than when they were expected first.
That said, Avalon seems to be filling in the gap pretty well.
G.
If it is a scam, this guys really made a huge profit. And to be honest, it looks like it is.